Merge branch 'master' into event-api

.github/javadoc-publish-clear

@@ -0,0 +1,3 @@
+**/*
+!.git
+!CNAME

.github/workflows/check-pr-style.yml

@@ -14,9 +14,9 @@ jobs:
     - name: Set up JDK 11
       uses: actions/setup-java@v1
       with:
-        java-version: 1.11
+        java-version: 11
     - name: Run java checkstyle
-      uses: nikitasavinov/checkstyle-action@d87d526a914fc5cb0b003908e35038dbb2d6e1b7
+      uses: nikitasavinov/checkstyle-action@0.3.1
       with:
         # Report level for reviewdog [info,warning,error]
         level: info
@@ -28,4 +28,4 @@ jobs:
         fail_on_error: false
         # Checkstyle config file
         checkstyle_config: minestom_checks.xml
-        checkstyle_version: "8.37"
+        checkstyle_version: "8.42"

.github/workflows/javadoc.yml

@@ -14,7 +14,7 @@ jobs:
     - name: Set up JDK 11
       uses: actions/setup-java@v1
       with:
-        java-version: 1.11
+        java-version: 11
     - name: Build javadoc
       run: gradle javadoc
       
@@ -25,3 +25,4 @@ jobs:
         BRANCH: javadoc
         FOLDER: docs
         GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
+        CLEAR_GLOBS_FILE: ".github/javadoc-publish-clear"

.github/workflows/tests.yml

@@ -16,7 +16,7 @@ jobs:
     - name: Set up JDK 11
       uses: actions/setup-java@v1
       with:
-        java-version: 1.11
+        java-version: 11
     - name: Grant execute permission for gradlew
       run: chmod +x gradlew
     - name: Setup gradle cache

build.gradle

@@ -2,9 +2,7 @@ import org.gradle.internal.os.OperatingSystem
 
 plugins {
     id 'java-library'
-    id 'java'
     id 'maven-publish'
-    id 'net.ltgt.apt' version '0.10'
     id 'org.jetbrains.kotlin.jvm' version '1.5.0'
     id 'checkstyle'
 }
@@ -12,7 +10,7 @@ plugins {
 group 'net.minestom.server'
 version '1.0'
 
-sourceCompatibility = 1.11
+sourceCompatibility = 11
 project.ext.lwjglVersion = "3.2.3"
 
 switch (OperatingSystem.current()) {
@@ -33,7 +31,6 @@ switch (OperatingSystem.current()) {
 allprojects {
     repositories {
         mavenCentral()
-        maven { url 'https://libraries.minecraft.net' }
         maven { url 'https://jitpack.io' }
         maven {
             name 'sponge'
@@ -54,7 +51,7 @@ allprojects {
         // see https://stackoverflow.com/a/56641766
         doLast {
             // Append the fix to the file
-            def searchScript = new File(destinationDir.getAbsolutePath() + '/search.js')
+            def searchScript = new File(destinationDir, '/search.js')
             searchScript.append '\n\n' +
                     'getURLPrefix = function(ui) {\n' +
                     '    return \'\';\n' +
@@ -63,7 +60,7 @@ allprojects {
     }
 
     checkstyle {
-        toolVersion "8.37"
+        toolVersion "8.42"
         configFile file("${projectDir}/minestom_checks.xml")
     }
 }
@@ -115,6 +112,10 @@ test {
     useJUnitPlatform()
 }
 
+tasks.withType(Zip).configureEach {
+    duplicatesStrategy DuplicatesStrategy.EXCLUDE
+}
+
 dependencies {
     // Junit Testing Framework
     testImplementation 'org.junit.jupiter:junit-jupiter-api:5.6.2'
@@ -130,9 +131,6 @@ dependencies {
     api 'io.netty:netty-transport-native-kqueue:4.1.63.Final:osx-x86_64'
     api 'io.netty.incubator:netty-incubator-transport-native-io_uring:0.0.5.Final:linux-x86_64'
 
-    // https://mvnrepository.com/artifact/org.apache.commons/commons-text
-    compile group: 'org.apache.commons', name: 'commons-text', version: '1.9'
-
     // https://mvnrepository.com/artifact/it.unimi.dsi/fastutil
     api 'it.unimi.dsi:fastutil:8.5.4'
 
@@ -154,9 +152,12 @@ dependencies {
     // https://mvnrepository.com/artifact/org.jline/jline
     implementation group: 'org.jline', name: 'jline', version: '3.20.0'
 
-    // Guava 21.0+ required for Mixin, but Authlib imports 17.0
+    // Jline compatibility for windows
+    // https://search.maven.org/artifact/org.fusesource.jansi/jansi/2.3.2/jar
+    implementation 'org.fusesource.jansi:jansi:2.3.2'
+
+    // Guava 21.0+ required for Mixin
     api 'com.google.guava:guava:30.1-jre'
-    api 'com.mojang:authlib:1.5.21'
 
     // Code modification
     api "org.ow2.asm:asm:${asmVersion}"

gradle/wrapper/gradle-wrapper.properties

@@ -1,5 +1,5 @@
 distributionBase=GRADLE_USER_HOME
 distributionPath=wrapper/dists
-distributionUrl=https\://services.gradle.org/distributions/gradle-6.8.1-bin.zip
+distributionUrl=https\://services.gradle.org/distributions/gradle-7.0.2-bin.zip
 zipStoreBase=GRADLE_USER_HOME
 zipStorePath=wrapper/dists

minestom_checks.xml

@@ -277,7 +277,7 @@
              value="CLASS_DEF, INTERFACE_DEF, ENUM_DEF, METHOD_DEF, CTOR_DEF, VARIABLE_DEF"/>
         </module>
         <module name="JavadocMethod">
-            <property name="scope" value="public"/>
+            <property name="accessModifiers" value="public"/>
             <property name="allowMissingParamTags" value="true"/>
             <property name="allowMissingReturnTag" value="true"/>
             <property name="allowedAnnotations" value="Override, Test"/>

src/main/java/net/minestom/server/MinecraftServer.java

@@ -826,6 +826,6 @@ public final class MinecraftServer {
     }
 
     private static int getThreadCount(@NotNull String property, int count) {
-        return Integer.getInteger(property, Math.min(1, count));
+        return Integer.getInteger(property, Math.max(1, count));
     }
 }

src/main/java/net/minestom/server/adventure/audience/PacketGroupingAudience.java

@@ -12,7 +12,8 @@ import net.kyori.adventure.title.Title;
 import net.minestom.server.MinecraftServer;
 import net.minestom.server.adventure.AdventurePacketConvertor;
 import net.minestom.server.entity.Player;
-import net.minestom.server.network.packet.server.play.ChatMessagePacket;
+import net.minestom.server.message.ChatPosition;
+import net.minestom.server.message.Messenger;
 import net.minestom.server.network.packet.server.play.PlayerListHeaderAndFooterPacket;
 import net.minestom.server.network.packet.server.play.TitlePacket;
 import net.minestom.server.utils.PacketUtils;
@@ -46,7 +47,7 @@ public interface PacketGroupingAudience extends ForwardingAudience {
 
     @Override
     default void sendMessage(@NotNull Identity source, @NotNull Component message, @NotNull MessageType type) {
-        PacketUtils.sendGroupedPacket(this.getPlayers(), new ChatMessagePacket(message, ChatMessagePacket.Position.fromMessageType(type), source.uuid()));
+        Messenger.sendMessage(this.getPlayers(), message, ChatPosition.fromMessageType(type), source.uuid());
     }
 
     @Override

src/main/java/net/minestom/server/color/Color.java

@@ -2,7 +2,8 @@ package net.minestom.server.color;
 
 import net.kyori.adventure.util.RGBLike;
 import net.minestom.server.chat.ChatColor;
-import org.apache.commons.lang3.Validate;
+import net.minestom.server.utils.MathUtils;
+import net.minestom.server.utils.validate.Check;
 import org.jetbrains.annotations.NotNull;
 
 import java.util.Objects;
@@ -38,17 +39,15 @@ public class Color implements RGBLike {
     /**
      * Creates a color from red, green, and blue components.
      *
-     * @param red the red component
+     * @param red   the red component
      * @param green the green component
-     * @param blue the blue component
+     * @param blue  the blue component
-     *
      * @throws IllegalArgumentException if any component value is not between 0-255 (inclusive)
      */
     public Color(int red, int green, int blue) {
-        Validate.isTrue(red >= 0 && red <= 255, "Red is not between 0-255: ", red);
+        Check.argCondition(!MathUtils.isBetween(red, 0, 255), "Red is not between 0-255: {0}", red);
-        Validate.isTrue(green >= 0 && green <= 255, "Green is not between 0-255: ", green);
+        Check.argCondition(!MathUtils.isBetween(green, 0, 255), "Green is not between 0-255: {0}", green);
-        Validate.isTrue(blue >= 0 && blue <= 255, "Blue is not between 0-255: ", blue);
+        Check.argCondition(!MathUtils.isBetween(blue, 0, 255), "Blue is not between 0-255: {0}", blue);
-
         this.red = red;
         this.green = green;
         this.blue = blue;
@@ -69,7 +68,7 @@ public class Color implements RGBLike {
      * @param red the red component, from 0 to 255
      */
     public void setRed(int red) {
-        Validate.isTrue(red >= 0 && red <= 255, "Red is not between 0-255: ", red);
+        Check.argCondition(!MathUtils.isBetween(red, 0, 255), "Red is not between 0-255: {0}", red);
         this.red = red;
     }
 
@@ -88,7 +87,7 @@ public class Color implements RGBLike {
      * @param green the red component, from 0 to 255
      */
     public void setGreen(int green) {
-        Validate.isTrue(green >= 0 && green <= 255, "Green is not between 0-255: ", green);
+        Check.argCondition(!MathUtils.isBetween(green, 0, 255), "Green is not between 0-255: {0}", green);
         this.green = green;
     }
 
@@ -107,7 +106,7 @@ public class Color implements RGBLike {
      * @param blue the red component, from 0 to 255
      */
     public void setBlue(int blue) {
-        Validate.isTrue(blue >= 0 && blue <= 255, "Blue is not between 0-255: ", blue);
+        Check.argCondition(!MathUtils.isBetween(blue, 0, 255), "Blue is not between 0-255: {0}", blue);
         this.blue = blue;
     }
 
@@ -132,8 +131,6 @@ public class Color implements RGBLike {
      * @param colors the colors
      */
     public void mixWith(@NotNull RGBLike... colors) {
-        Validate.noNullElements(colors, "Colors cannot be null");
-
         // store the current highest component
         int max = Math.max(Math.max(this.red, this.green), this.blue);
 

src/main/java/net/minestom/server/command/builder/Command.java

@@ -7,7 +7,7 @@ import net.minestom.server.command.CommandSender;
 import net.minestom.server.command.builder.arguments.*;
 import net.minestom.server.command.builder.arguments.minecraft.SuggestionType;
 import net.minestom.server.command.builder.condition.CommandCondition;
-import org.apache.commons.lang3.StringUtils;
+import net.minestom.server.utils.StringUtils;
 import org.jetbrains.annotations.NotNull;
 import org.jetbrains.annotations.Nullable;
 import org.slf4j.Logger;

src/main/java/net/minestom/server/command/builder/CommandContext.java

@@ -1,7 +1,7 @@
 package net.minestom.server.command.builder;
 
 import net.minestom.server.command.builder.arguments.Argument;
-import org.apache.commons.lang3.StringUtils;
+import net.minestom.server.utils.StringUtils;
 import org.jetbrains.annotations.NotNull;
 import org.jetbrains.annotations.Nullable;
 
@@ -44,10 +44,16 @@ public class CommandContext {
     }
 
     public <T> T get(@NotNull String identifier) {
-        return (T) args.computeIfAbsent(identifier, s -> {
+        return (T) args.get(identifier);
-            throw new NullPointerException(
+    }
-                    "The argument with the id '" + identifier + "' has no value assigned, be sure to check your arguments id, your syntax, and that you do not change the argument id dynamically.");
+
-        });
+    public <T> T getOrDefault(@NotNull Argument<T> argument, T defaultValue) {
+        return getOrDefault(argument.getId(), defaultValue);
+    }
+
+    public <T> T getOrDefault(@NotNull String identifier, T defaultValue) {
+        T value;
+        return (value = get(identifier)) != null ? value : defaultValue;
     }
 
     public boolean has(@NotNull Argument<?> argument) {

src/main/java/net/minestom/server/command/builder/CommandDispatcher.java

@@ -10,7 +10,7 @@ import net.minestom.server.command.builder.parser.CommandParser;
 import net.minestom.server.command.builder.parser.CommandQueryResult;
 import net.minestom.server.command.builder.parser.CommandSuggestionHolder;
 import net.minestom.server.command.builder.parser.ValidSyntaxHolder;
-import org.apache.commons.lang3.StringUtils;
+import net.minestom.server.utils.StringUtils;
 import org.jetbrains.annotations.NotNull;
 import org.jetbrains.annotations.Nullable;
 

src/main/java/net/minestom/server/command/builder/CommandSyntax.java

@@ -3,7 +3,7 @@ package net.minestom.server.command.builder;
 import net.minestom.server.command.builder.arguments.Argument;
 import net.minestom.server.command.builder.condition.CommandCondition;
 import net.minestom.server.entity.Player;
-import org.apache.commons.lang3.StringUtils;
+import net.minestom.server.utils.StringUtils;
 import org.jetbrains.annotations.NotNull;
 import org.jetbrains.annotations.Nullable;
 

src/main/java/net/minestom/server/command/builder/ParsedCommand.java

@@ -1,5 +1,6 @@
 package net.minestom.server.command.builder;
 
+import net.minestom.server.MinecraftServer;
 import net.minestom.server.command.CommandSender;
 import net.minestom.server.command.builder.condition.CommandCondition;
 import net.minestom.server.command.builder.exception.ArgumentSyntaxException;
@@ -54,11 +55,19 @@ public class ParsedCommand {
                 final CommandCondition commandCondition = syntax.getCommandCondition();
                 if (commandCondition == null || commandCondition.canUse(source, commandString)) {
                     context.retrieveDefaultValues(syntax.getDefaultValuesMap());
-                    executor.apply(source, context);
+                    try {
+                        executor.apply(source, context);
+                    } catch (Exception exception) {
+                        MinecraftServer.getExceptionManager().handleException(exception);
+                    }
                 }
             } else {
                 // The executor is probably the default one
-                executor.apply(source, context);
+                try {
+                    executor.apply(source, context);
+                } catch (Exception exception) {
+                    MinecraftServer.getExceptionManager().handleException(exception);
+                }
             }
         } else if (callback != null && argumentSyntaxException != null) {
             // No syntax has been validated but the faulty argument with a callback has been found

src/main/java/net/minestom/server/command/builder/arguments/Argument.java

@@ -195,23 +195,48 @@ public abstract class Argument<T> {
         return this;
     }
 
+    /**
+     * Sets the default value supplier of the argument.
+     *
+     * @param defaultValue the default argument value
+     * @return 'this' for chaining
+     */
     @NotNull
-    public Argument<T> setDefaultValue(@Nullable T defaultValue) {
+    public Argument<T> setDefaultValue(@NotNull T defaultValue) {
         this.defaultValue = () -> defaultValue;
         return this;
     }
 
+    /**
+     * Gets the suggestion callback of the argument
+     *
+     * @see #setSuggestionCallback
+     * @return the suggestion callback of the argument, null if it doesn't exist
+     */
     @Nullable
     public SuggestionCallback getSuggestionCallback() {
         return suggestionCallback;
     }
 
+    /**
+     * Sets the suggestion callback (for dynamic tab completion) of this argument.
+     * <p>
+     * Note: This will not automatically filter arguments by user input.
+     *
+     * @param suggestionCallback The suggestion callback to set.
+     * @return 'this' for chaining
+     */
     @Beta
     public Argument<T> setSuggestionCallback(@NotNull SuggestionCallback suggestionCallback) {
         this.suggestionCallback = suggestionCallback;
         return this;
     }
 
+    /**
+     * Check if the argument has a suggestion.
+     *
+     * @return If this argument has a suggestion.
+     */
     public boolean hasSuggestion() {
         return suggestionCallback != null;
     }

src/main/java/net/minestom/server/command/builder/arguments/ArgumentCommand.java

@@ -7,7 +7,7 @@ import net.minestom.server.command.builder.CommandResult;
 import net.minestom.server.command.builder.NodeMaker;
 import net.minestom.server.command.builder.exception.ArgumentSyntaxException;
 import net.minestom.server.network.packet.server.play.DeclareCommandsPacket;
-import org.apache.commons.lang3.StringUtils;
+import net.minestom.server.utils.StringUtils;
 import org.jetbrains.annotations.NotNull;
 
 public class ArgumentCommand extends Argument<CommandResult> {

src/main/java/net/minestom/server/command/builder/arguments/ArgumentDynamicStringArray.java

@@ -7,7 +7,7 @@ import net.minestom.server.command.builder.suggestion.SuggestionCallback;
 import net.minestom.server.network.packet.server.play.DeclareCommandsPacket;
 import net.minestom.server.utils.binary.BinaryWriter;
 import net.minestom.server.utils.callback.validator.StringArrayValidator;
-import org.apache.commons.lang3.StringUtils;
+import net.minestom.server.utils.StringUtils;
 import org.jetbrains.annotations.NotNull;
 import org.jetbrains.annotations.Nullable;
 

src/main/java/net/minestom/server/command/builder/arguments/ArgumentDynamicWord.java

@@ -6,9 +6,9 @@ import net.minestom.server.command.builder.arguments.minecraft.SuggestionType;
 import net.minestom.server.command.builder.exception.ArgumentSyntaxException;
 import net.minestom.server.command.builder.suggestion.SuggestionCallback;
 import net.minestom.server.network.packet.server.play.DeclareCommandsPacket;
+import net.minestom.server.utils.StringUtils;
 import net.minestom.server.utils.binary.BinaryWriter;
 import net.minestom.server.utils.callback.validator.StringValidator;
-import org.apache.commons.lang3.StringUtils;
 import org.jetbrains.annotations.NotNull;
 import org.jetbrains.annotations.Nullable;
 

src/main/java/net/minestom/server/command/builder/arguments/ArgumentGroup.java

@@ -5,7 +5,7 @@ import net.minestom.server.command.builder.NodeMaker;
 import net.minestom.server.command.builder.exception.ArgumentSyntaxException;
 import net.minestom.server.command.builder.parser.CommandParser;
 import net.minestom.server.command.builder.parser.ValidSyntaxHolder;
-import org.apache.commons.lang3.StringUtils;
+import net.minestom.server.utils.StringUtils;
 import org.jetbrains.annotations.NotNull;
 
 import java.util.ArrayList;

src/main/java/net/minestom/server/command/builder/arguments/ArgumentLoop.java

@@ -3,7 +3,7 @@ package net.minestom.server.command.builder.arguments;
 import net.minestom.server.command.builder.NodeMaker;
 import net.minestom.server.command.builder.exception.ArgumentSyntaxException;
 import net.minestom.server.network.packet.server.play.DeclareCommandsPacket;
-import org.apache.commons.lang3.StringUtils;
+import net.minestom.server.utils.StringUtils;
 import org.jetbrains.annotations.NotNull;
 
 import java.util.ArrayList;

src/main/java/net/minestom/server/command/builder/arguments/ArgumentString.java

@@ -4,8 +4,8 @@ import io.netty.util.internal.StringUtil;
 import net.minestom.server.command.builder.NodeMaker;
 import net.minestom.server.command.builder.exception.ArgumentSyntaxException;
 import net.minestom.server.network.packet.server.play.DeclareCommandsPacket;
+import net.minestom.server.utils.StringUtils;
 import net.minestom.server.utils.binary.BinaryWriter;
-import org.apache.commons.text.StringEscapeUtils;
 import org.jetbrains.annotations.NotNull;
 
 /**
@@ -75,7 +75,7 @@ public class ArgumentString extends Argument<String> {
             }
         }
 
-        return StringEscapeUtils.unescapeJava(input);
+        return StringUtils.unescapeJavaString(input);
     }
 
     @Override

src/main/java/net/minestom/server/command/builder/arguments/ArgumentStringArray.java

@@ -2,8 +2,8 @@ package net.minestom.server.command.builder.arguments;
 
 import net.minestom.server.command.builder.NodeMaker;
 import net.minestom.server.network.packet.server.play.DeclareCommandsPacket;
+import net.minestom.server.utils.StringUtils;
 import net.minestom.server.utils.binary.BinaryWriter;
-import org.apache.commons.lang3.StringUtils;
 import org.jetbrains.annotations.NotNull;
 
 import java.util.regex.Pattern;

src/main/java/net/minestom/server/command/builder/arguments/ArgumentWord.java

@@ -5,7 +5,7 @@ import net.minestom.server.command.builder.exception.ArgumentSyntaxException;
 import net.minestom.server.network.packet.server.play.DeclareCommandsPacket;
 import net.minestom.server.utils.binary.BinaryWriter;
 import net.minestom.server.utils.validate.Check;
-import org.apache.commons.lang3.StringUtils;
+import net.minestom.server.utils.StringUtils;
 import org.jetbrains.annotations.NotNull;
 import org.jetbrains.annotations.Nullable;
 

src/main/java/net/minestom/server/command/builder/arguments/minecraft/ArgumentEntity.java

@@ -10,7 +10,7 @@ import net.minestom.server.registry.Registries;
 import net.minestom.server.utils.binary.BinaryWriter;
 import net.minestom.server.utils.entity.EntityFinder;
 import net.minestom.server.utils.math.IntRange;
-import org.apache.commons.lang3.StringUtils;
+import net.minestom.server.utils.StringUtils;
 import org.jetbrains.annotations.NotNull;
 
 import java.util.Arrays;

src/main/java/net/minestom/server/command/builder/arguments/minecraft/ArgumentResourceLocation.java

@@ -4,7 +4,7 @@ import net.minestom.server.command.builder.NodeMaker;
 import net.minestom.server.command.builder.arguments.Argument;
 import net.minestom.server.command.builder.exception.ArgumentSyntaxException;
 import net.minestom.server.network.packet.server.play.DeclareCommandsPacket;
-import org.apache.commons.lang3.StringUtils;
+import net.minestom.server.utils.StringUtils;
 import org.jetbrains.annotations.NotNull;
 
 public class ArgumentResourceLocation extends Argument<String> {

src/main/java/net/minestom/server/command/builder/arguments/relative/ArgumentRelativeBlockPosition.java

@@ -5,7 +5,7 @@ import net.minestom.server.command.builder.exception.ArgumentSyntaxException;
 import net.minestom.server.network.packet.server.play.DeclareCommandsPacket;
 import net.minestom.server.utils.BlockPosition;
 import net.minestom.server.utils.location.RelativeBlockPosition;
-import org.apache.commons.lang3.StringUtils;
+import net.minestom.server.utils.StringUtils;
 import org.jetbrains.annotations.NotNull;
 
 /**

src/main/java/net/minestom/server/command/builder/arguments/relative/ArgumentRelativeVec2.java

@@ -5,7 +5,7 @@ import net.minestom.server.command.builder.exception.ArgumentSyntaxException;
 import net.minestom.server.network.packet.server.play.DeclareCommandsPacket;
 import net.minestom.server.utils.Vector;
 import net.minestom.server.utils.location.RelativeVec;
-import org.apache.commons.lang3.StringUtils;
+import net.minestom.server.utils.StringUtils;
 import org.jetbrains.annotations.NotNull;
 
 /**

src/main/java/net/minestom/server/command/builder/arguments/relative/ArgumentRelativeVec3.java

@@ -5,7 +5,7 @@ import net.minestom.server.command.builder.exception.ArgumentSyntaxException;
 import net.minestom.server.network.packet.server.play.DeclareCommandsPacket;
 import net.minestom.server.utils.Vector;
 import net.minestom.server.utils.location.RelativeVec;
-import org.apache.commons.lang3.StringUtils;
+import net.minestom.server.utils.StringUtils;
 import org.jetbrains.annotations.NotNull;
 
 /**

src/main/java/net/minestom/server/command/builder/parser/ArgumentParser.java

@@ -11,7 +11,7 @@ import net.minestom.server.command.builder.arguments.relative.ArgumentRelativeBl
 import net.minestom.server.command.builder.arguments.relative.ArgumentRelativeVec2;
 import net.minestom.server.command.builder.arguments.relative.ArgumentRelativeVec3;
 import net.minestom.server.command.builder.exception.ArgumentSyntaxException;
-import org.apache.commons.lang3.StringUtils;
+import net.minestom.server.utils.StringUtils;
 import org.jetbrains.annotations.NotNull;
 import org.jetbrains.annotations.Nullable;
 

src/main/java/net/minestom/server/command/builder/parser/CommandParser.java

@@ -7,7 +7,7 @@ import net.minestom.server.command.builder.Command;
 import net.minestom.server.command.builder.CommandContext;
 import net.minestom.server.command.builder.CommandSyntax;
 import net.minestom.server.command.builder.arguments.Argument;
-import org.apache.commons.lang3.StringUtils;
+import net.minestom.server.utils.StringUtils;
 import org.jetbrains.annotations.NotNull;
 import org.jetbrains.annotations.Nullable;
 

src/main/java/net/minestom/server/entity/Entity.java

@@ -268,7 +268,7 @@ public class Entity implements Viewable, Tickable, EventHandler, DataContainer,
         final ChunkCallback endCallback = (chunk) -> {
             refreshPosition(teleportPosition);
 
-            synchronizePosition();
+            synchronizePosition(true);
 
             OptionalCallback.execute(callback);
         };
@@ -552,7 +552,10 @@ public class Entity implements Viewable, Tickable, EventHandler, DataContainer,
 
                 // Apply the position if changed
                 if (!finalVelocityPosition.isSimilar(position)) {
-                    refreshPosition(finalVelocityPosition);
+                    refreshPosition(finalVelocityPosition.getX(),
+                            finalVelocityPosition.getY(),
+                            finalVelocityPosition.getZ());
+                    sendPositionUpdate(true);
                 }
 
 
@@ -594,7 +597,7 @@ public class Entity implements Viewable, Tickable, EventHandler, DataContainer,
 
                 // Synchronization and packets...
                 if (!isNettyClient) {
-                    synchronizePosition();
+                    synchronizePosition(true);
                 }
                 // Verify if velocity packet has to be sent
                 if (hasVelocity() || (!isNettyClient && gravityTickCount > 0)) {
@@ -665,7 +668,7 @@ public class Entity implements Viewable, Tickable, EventHandler, DataContainer,
 
         // Scheduled synchronization
         if (!Cooldown.hasCooldown(time, lastAbsoluteSynchronizationTime, getSynchronizationCooldown())) {
-            synchronizePosition();
+            synchronizePosition(false);
         }
 
         if (shouldRemove() && !MinecraftServer.isStopping()) {
@@ -677,28 +680,28 @@ public class Entity implements Viewable, Tickable, EventHandler, DataContainer,
      * Sends the correct packets to update the entity's position, should be called
      * every tick. The movement is checked inside the method!
      * <p>
-     *     The following packets are sent to viewers (check are performed in this order):
+     * The following packets are sent to viewers (check are performed in this order):
-     *     <ol>
+     * <ol>
-     *         <li>{@link EntityTeleportPacket} if {@code distanceX > 8 || distanceY > 8 || distanceZ > 8}
+     *     <li>{@link EntityTeleportPacket} if {@code distanceX > 8 || distanceY > 8 || distanceZ > 8}
-     *          <i>(performed using {@link #synchronizePosition()})</i></li>
+     *      <i>(performed using {@link #synchronizePosition(boolean)})</i></li>
-     *         <li>{@link EntityPositionAndRotationPacket} if {@code positionChange && viewChange}</li>
+     *     <li>{@link EntityPositionAndRotationPacket} if {@code positionChange && viewChange}</li>
-     *         <li>{@link EntityPositionPacket} if {@code positionChange}</li>
+     *     <li>{@link EntityPositionPacket} if {@code positionChange}</li>
-     *         <li>{@link EntityRotationPacket} and {@link EntityHeadLookPacket} if {@code viewChange}</li>
+     *     <li>{@link EntityRotationPacket} and {@link EntityHeadLookPacket} if {@code viewChange}</li>
-     *     </ol>
+     * </ol>
-     *     In case of a player's position and/or view change an additional {@link PlayerPositionAndLookPacket}
+     * In case of a player's position and/or view change an additional {@link PlayerPositionAndLookPacket}
-     *     is sent to self.
+     * is sent to self.
      *
      * @param clientSide {@code true} if the client triggered this action
      */
     protected void sendPositionUpdate(final boolean clientSide) {
         final boolean viewChange = !position.hasSimilarView(lastSyncedPosition);
-        final double distanceX = Math.abs(position.getX()-lastSyncedPosition.getX());
+        final double distanceX = Math.abs(position.getX() - lastSyncedPosition.getX());
-        final double distanceY = Math.abs(position.getY()-lastSyncedPosition.getY());
+        final double distanceY = Math.abs(position.getY() - lastSyncedPosition.getY());
-        final double distanceZ = Math.abs(position.getZ()-lastSyncedPosition.getZ());
+        final double distanceZ = Math.abs(position.getZ() - lastSyncedPosition.getZ());
-        final boolean positionChange = (distanceX+distanceY+distanceZ) > 0;
+        final boolean positionChange = (distanceX + distanceY + distanceZ) > 0;
 
         if (distanceX > 8 || distanceY > 8 || distanceZ > 8) {
-            synchronizePosition();
+            synchronizePosition(true);
             // #synchronizePosition sets sync fields, it's safe to return
             return;
         } else if (positionChange && viewChange) {
@@ -742,7 +745,7 @@ public class Entity implements Viewable, Tickable, EventHandler, DataContainer,
             final PlayerPositionAndLookPacket playerPositionAndLookPacket = new PlayerPositionAndLookPacket();
             playerPositionAndLookPacket.flags = 0b111;
             playerPositionAndLookPacket.position = position.clone().subtract(lastSyncedPosition.getX(), lastSyncedPosition.getY(), lastSyncedPosition.getZ());
-            playerPositionAndLookPacket.teleportId = ((Player)this).getNextTeleportId();
+            playerPositionAndLookPacket.teleportId = ((Player) this).getNextTeleportId();
             ((Player) this).getPlayerConnection().sendPacket(playerPositionAndLookPacket);
         }
 
@@ -1393,8 +1396,7 @@ public class Entity implements Viewable, Tickable, EventHandler, DataContainer,
     /**
      * Updates internal fields and sends updates
      *
-     * @param position      the new position
+     * @param position the new position
-     *
      * @see #refreshPosition(double, double, double)
      * @see #refreshView(float, float)
      * @see #sendPositionUpdate(boolean)
@@ -1583,9 +1585,12 @@ public class Entity implements Viewable, Tickable, EventHandler, DataContainer,
      * {@link EntityTeleportPacket} to viewers, in case of a player this is
      * overridden in order to send an additional {@link PlayerPositionAndLookPacket}
      * to itself.
+     *
+     * @param includeSelf if {@code true} and this is a {@link Player} an additional {@link PlayerPositionAndLookPacket}
+     *                    will be sent to the player itself
      */
     @ApiStatus.Internal
-    protected void synchronizePosition() {
+    protected void synchronizePosition(boolean includeSelf) {
         final Position pos = position.clone();
         final EntityTeleportPacket entityTeleportPacket = new EntityTeleportPacket();
         entityTeleportPacket.entityId = getEntityId();

src/main/java/net/minestom/server/entity/EquipmentSlot.java

@@ -0,0 +1,42 @@
+package net.minestom.server.entity;
+
+import net.minestom.server.event.item.EntityEquipEvent;
+import net.minestom.server.item.attribute.AttributeSlot;
+import org.jetbrains.annotations.NotNull;
+
+public enum EquipmentSlot {
+    MAIN_HAND,
+    OFF_HAND,
+    BOOTS,
+    LEGGINGS,
+    CHESTPLATE,
+    HELMET;
+
+    public boolean isHand() {
+        return this == MAIN_HAND || this == OFF_HAND;
+    }
+
+    public boolean isArmor() {
+        return !isHand();
+    }
+
+    @NotNull
+    public static EquipmentSlot fromAttributeSlot(AttributeSlot attributeSlot) {
+        switch (attributeSlot) {
+            case MAINHAND:
+                return MAIN_HAND;
+            case OFFHAND:
+                return OFF_HAND;
+            case FEET:
+                return BOOTS;
+            case LEGS:
+                return LEGGINGS;
+            case CHEST:
+                return CHESTPLATE;
+            case HEAD:
+                return HELMET;
+        }
+        throw new IllegalStateException("Something weird happened");
+    }
+
+}

src/main/java/net/minestom/server/entity/LivingEntity.java

@@ -10,7 +10,7 @@ import net.minestom.server.entity.metadata.LivingEntityMeta;
 import net.minestom.server.event.entity.EntityDamageEvent;
 import net.minestom.server.event.entity.EntityDeathEvent;
 import net.minestom.server.event.entity.EntityFireEvent;
-import net.minestom.server.event.item.ArmorEquipEvent;
+import net.minestom.server.event.item.EntityEquipEvent;
 import net.minestom.server.event.item.PickupItemEvent;
 import net.minestom.server.instance.Chunk;
 import net.minestom.server.instance.block.Block;
@@ -127,8 +127,8 @@ public class LivingEntity extends Entity implements EquipmentHandler {
 
     @Override
     public void setItemInMainHand(@NotNull ItemStack itemStack) {
-        this.mainHandItem = itemStack;
+        this.mainHandItem = getEquipmentItem(itemStack, EquipmentSlot.MAIN_HAND);
-        syncEquipment(EntityEquipmentPacket.Slot.MAIN_HAND);
+        syncEquipment(EquipmentSlot.MAIN_HAND);
     }
 
     @NotNull
@@ -139,8 +139,8 @@ public class LivingEntity extends Entity implements EquipmentHandler {
 
     @Override
     public void setItemInOffHand(@NotNull ItemStack itemStack) {
-        this.offHandItem = itemStack;
+        this.offHandItem = getEquipmentItem(itemStack, EquipmentSlot.OFF_HAND);
-        syncEquipment(EntityEquipmentPacket.Slot.OFF_HAND);
+        syncEquipment(EquipmentSlot.OFF_HAND);
     }
 
     @NotNull
@@ -151,8 +151,8 @@ public class LivingEntity extends Entity implements EquipmentHandler {
 
     @Override
     public void setHelmet(@NotNull ItemStack itemStack) {
-        this.helmet = getEquipmentItem(itemStack, ArmorEquipEvent.ArmorSlot.HELMET);
+        this.helmet = getEquipmentItem(itemStack, EquipmentSlot.HELMET);
-        syncEquipment(EntityEquipmentPacket.Slot.HELMET);
+        syncEquipment(EquipmentSlot.HELMET);
     }
 
     @NotNull
@@ -163,8 +163,8 @@ public class LivingEntity extends Entity implements EquipmentHandler {
 
     @Override
     public void setChestplate(@NotNull ItemStack itemStack) {
-        this.chestplate = getEquipmentItem(itemStack, ArmorEquipEvent.ArmorSlot.CHESTPLATE);
+        this.chestplate = getEquipmentItem(itemStack, EquipmentSlot.CHESTPLATE);
-        syncEquipment(EntityEquipmentPacket.Slot.CHESTPLATE);
+        syncEquipment(EquipmentSlot.CHESTPLATE);
     }
 
     @NotNull
@@ -175,8 +175,8 @@ public class LivingEntity extends Entity implements EquipmentHandler {
 
     @Override
     public void setLeggings(@NotNull ItemStack itemStack) {
-        this.leggings = getEquipmentItem(itemStack, ArmorEquipEvent.ArmorSlot.LEGGINGS);
+        this.leggings = getEquipmentItem(itemStack, EquipmentSlot.LEGGINGS);
-        syncEquipment(EntityEquipmentPacket.Slot.LEGGINGS);
+        syncEquipment(EquipmentSlot.LEGGINGS);
     }
 
     @NotNull
@@ -187,14 +187,14 @@ public class LivingEntity extends Entity implements EquipmentHandler {
 
     @Override
     public void setBoots(@NotNull ItemStack itemStack) {
-        this.boots = getEquipmentItem(itemStack, ArmorEquipEvent.ArmorSlot.BOOTS);
+        this.boots = getEquipmentItem(itemStack, EquipmentSlot.BOOTS);
-        syncEquipment(EntityEquipmentPacket.Slot.BOOTS);
+        syncEquipment(EquipmentSlot.BOOTS);
     }
 
-    private ItemStack getEquipmentItem(@NotNull ItemStack itemStack, @NotNull ArmorEquipEvent.ArmorSlot armorSlot) {
+    private ItemStack getEquipmentItem(@NotNull ItemStack itemStack, @NotNull EquipmentSlot slot) {
-        ArmorEquipEvent armorEquipEvent = new ArmorEquipEvent(this, itemStack, armorSlot);
+        EntityEquipEvent entityEquipEvent = new EntityEquipEvent(this, itemStack, slot);
-        callEvent(ArmorEquipEvent.class, armorEquipEvent);
+        callEvent(EntityEquipEvent.class, entityEquipEvent);
-        return armorEquipEvent.getArmorItem();
+        return entityEquipEvent.getEquippedItem();
     }
 
     @Override
@@ -595,6 +595,14 @@ public class LivingEntity extends Entity implements EquipmentHandler {
         }
     }
 
+    public boolean isFlyingWithElytra() {
+        return this.entityMeta.isFlyingWithElytra();
+    }
+
+    public void setFlyingWithElytra(boolean isFlying) {
+        this.entityMeta.setFlyingWithElytra(isFlying);
+    }
+    
     /**
      * Used to change the {@code isDead} internal field.
      *

src/main/java/net/minestom/server/entity/Player.java

@@ -38,12 +38,15 @@ import net.minestom.server.event.player.*;
 import net.minestom.server.instance.Chunk;
 import net.minestom.server.instance.Instance;
 import net.minestom.server.instance.block.CustomBlock;
+import net.minestom.server.message.ChatMessageType;
+import net.minestom.server.message.ChatPosition;
 import net.minestom.server.inventory.Inventory;
 import net.minestom.server.inventory.PlayerInventory;
 import net.minestom.server.item.ItemStack;
 import net.minestom.server.item.Material;
 import net.minestom.server.item.metadata.WrittenBookMeta;
 import net.minestom.server.listener.PlayerDiggingListener;
+import net.minestom.server.message.Messenger;
 import net.minestom.server.network.ConnectionManager;
 import net.minestom.server.network.ConnectionState;
 import net.minestom.server.network.PlayerProvider;
@@ -661,7 +664,7 @@ public class Player extends LivingEntity implements CommandSender, Localizable,
         }
 
         if (dimensionChange || firstSpawn) {
-            synchronizePosition(); // So the player doesn't get stuck
+            synchronizePosition(true); // So the player doesn't get stuck
             this.inventory.update();
         }
 
@@ -730,8 +733,7 @@ public class Player extends LivingEntity implements CommandSender, Localizable,
 
     @Override
     public void sendMessage(@NotNull Identity source, @NotNull Component message, @NotNull MessageType type) {
-        ChatMessagePacket chatMessagePacket = new ChatMessagePacket(message, ChatMessagePacket.Position.fromMessageType(type), source.uuid());
+        Messenger.sendMessage(this, message, ChatPosition.fromMessageType(type), source.uuid());
-        playerConnection.sendPacket(chatMessagePacket);
     }
 
     /**
@@ -1984,18 +1986,20 @@ public class Player extends LivingEntity implements CommandSender, Localizable,
     }
 
     /**
-     * @see Entity#synchronizePosition()
+     * @see Entity#synchronizePosition(boolean)
      */
     @Override
     @ApiStatus.Internal
-    protected void synchronizePosition() {
+    protected void synchronizePosition(boolean includeSelf) {
-        final PlayerPositionAndLookPacket positionAndLookPacket = new PlayerPositionAndLookPacket();
+        if (includeSelf) {
-        positionAndLookPacket.position = position.clone();
+            final PlayerPositionAndLookPacket positionAndLookPacket = new PlayerPositionAndLookPacket();
-        positionAndLookPacket.flags = 0x00;
+            positionAndLookPacket.position = position.clone();
-        positionAndLookPacket.teleportId = teleportId.incrementAndGet();
+            positionAndLookPacket.flags = 0x00;
-        playerConnection.sendPacket(positionAndLookPacket);
+            positionAndLookPacket.teleportId = teleportId.incrementAndGet();
+            playerConnection.sendPacket(positionAndLookPacket);
+        }
 
-        super.synchronizePosition();
+        super.synchronizePosition(includeSelf);
     }
 
     /**
@@ -2223,6 +2227,10 @@ public class Player extends LivingEntity implements CommandSender, Localizable,
 
     public void refreshOnGround(boolean onGround) {
         this.onGround = onGround;
+        if(this.onGround && this.isFlyingWithElytra()) {
+            this.setFlyingWithElytra(false);
+            this.callEvent(PlayerStopFlyingWithElytraEvent.class, new PlayerStopFlyingWithElytraEvent(this));
+        }
     }
 
     /**
@@ -2256,7 +2264,7 @@ public class Player extends LivingEntity implements CommandSender, Localizable,
      */
     public void refreshHeldSlot(byte slot) {
         this.heldSlot = slot;
-        syncEquipment(EntityEquipmentPacket.Slot.MAIN_HAND);
+        syncEquipment(EquipmentSlot.MAIN_HAND);
 
         refreshEating(null);
     }
@@ -2578,6 +2586,10 @@ public class Player extends LivingEntity implements CommandSender, Localizable,
         RIGHT
     }
 
+    /**
+     * @deprecated See {@link ChatMessageType}
+     */
+    @Deprecated
     public enum ChatMode {
         ENABLED,
         COMMANDS_ONLY,
@@ -2588,7 +2600,7 @@ public class Player extends LivingEntity implements CommandSender, Localizable,
 
         private String locale;
         private byte viewDistance;
-        private ChatMode chatMode;
+        private ChatMessageType chatMessageType;
         private boolean chatColors;
         private byte displayedSkinParts;
         private MainHand mainHand;
@@ -2619,9 +2631,20 @@ public class Player extends LivingEntity implements CommandSender, Localizable,
          * Gets the player chat mode.
          *
          * @return the player chat mode
+         * @deprecated Use {@link #getChatMessageType()}
          */
+        @Deprecated
         public ChatMode getChatMode() {
-            return chatMode;
+            return ChatMode.values()[chatMessageType.ordinal()];
+        }
+
+        /**
+         * Gets the messages this player wants to receive.
+         *
+         * @return the messages
+         */
+        public @Nullable ChatMessageType getChatMessageType() {
+            return chatMessageType;
         }
 
         /**
@@ -2653,19 +2676,19 @@ public class Player extends LivingEntity implements CommandSender, Localizable,
          *
          * @param locale             the player locale
          * @param viewDistance       the player view distance
-         * @param chatMode           the player chat mode
+         * @param chatMessageType       the chat messages the player wishes to receive
-         * @param chatColors         the player chat colors
+         * @param chatColors         if chat colors should be displayed
          * @param displayedSkinParts the player displayed skin parts
          * @param mainHand           the player main hand
          */
-        public void refresh(String locale, byte viewDistance, ChatMode chatMode, boolean chatColors,
+        public void refresh(String locale, byte viewDistance, ChatMessageType chatMessageType, boolean chatColors,
                             byte displayedSkinParts, MainHand mainHand) {
 
             final boolean viewDistanceChanged = this.viewDistance != viewDistance;
 
             this.locale = locale;
             this.viewDistance = viewDistance;
-            this.chatMode = chatMode;
+            this.chatMessageType = chatMessageType;
             this.chatColors = chatColors;
             this.displayedSkinParts = displayedSkinParts;
             this.mainHand = mainHand;

src/main/java/net/minestom/server/entity/fakeplayer/FakePlayer.java

@@ -124,17 +124,22 @@ public class FakePlayer extends Player implements NavigableEntity {
         super.setInstance(instance);
     }
 
+    @Override
+    protected boolean addViewer0(@NotNull Player player) {
+        final boolean result = super.addViewer0(player);
+        if (result) {
+            handleTabList(player.getPlayerConnection());
+        }
+        return result;
+    }
+
     /**
      * {@inheritDoc}
      */
     @Override
     protected void showPlayer(@NotNull PlayerConnection connection) {
         super.showPlayer(connection);
-        if (!option.isInTabList()) {
+        handleTabList(connection);
-            // Remove from tab-list
-            MinecraftServer.getSchedulerManager().buildTask(() -> connection.sendPacket(getRemovePlayerToList())).delay(20, TimeUnit.TICK).schedule();
-        }
-
     }
 
     @NotNull
@@ -142,4 +147,11 @@ public class FakePlayer extends Player implements NavigableEntity {
     public Navigator getNavigator() {
         return navigator;
     }
+
+    private void handleTabList(PlayerConnection connection) {
+        if (!option.isInTabList()) {
+            // Remove from tab-list
+            MinecraftServer.getSchedulerManager().buildTask(() -> connection.sendPacket(getRemovePlayerToList())).delay(20, TimeUnit.TICK).schedule();
+        }
+    }
 }

src/main/java/net/minestom/server/entity/metadata/animal/FoxMeta.java

@@ -3,8 +3,8 @@ package net.minestom.server.entity.metadata.animal;
 import net.minestom.server.entity.Entity;
 import net.minestom.server.entity.Metadata;
 import org.jetbrains.annotations.NotNull;
+import org.jetbrains.annotations.Nullable;
 
-import javax.annotation.Nullable;
 import java.util.UUID;
 
 public class FoxMeta extends AnimalMeta {

src/main/java/net/minestom/server/entity/type/decoration/EntityArmorStand.java

@@ -1,13 +1,9 @@
 package net.minestom.server.entity.type.decoration;
 
-import net.minestom.server.entity.EntityType;
+import net.minestom.server.entity.*;
-import net.minestom.server.entity.Metadata;
+import net.minestom.server.event.item.EntityEquipEvent;
-import net.minestom.server.entity.ObjectEntity;
-import net.minestom.server.entity.Player;
-import net.minestom.server.event.item.ArmorEquipEvent;
 import net.minestom.server.inventory.EquipmentHandler;
 import net.minestom.server.item.ItemStack;
-import net.minestom.server.network.packet.server.play.EntityEquipmentPacket;
 import net.minestom.server.utils.Position;
 import net.minestom.server.utils.Vector;
 import net.minestom.server.utils.binary.BitmaskUtil;
@@ -73,8 +69,8 @@ public class EntityArmorStand extends ObjectEntity implements EquipmentHandler {
 
     @Override
     public void setItemInMainHand(@NotNull ItemStack itemStack) {
-        this.mainHandItem = itemStack;
+        this.mainHandItem = getEquipmentItem(itemStack, EquipmentSlot.MAIN_HAND);
-        syncEquipment(EntityEquipmentPacket.Slot.MAIN_HAND);
+        syncEquipment(EquipmentSlot.MAIN_HAND);
     }
 
     @NotNull
@@ -85,8 +81,8 @@ public class EntityArmorStand extends ObjectEntity implements EquipmentHandler {
 
     @Override
     public void setItemInOffHand(@NotNull ItemStack itemStack) {
-        this.offHandItem = itemStack;
+        this.offHandItem = getEquipmentItem(itemStack, EquipmentSlot.OFF_HAND);
-        syncEquipment(EntityEquipmentPacket.Slot.OFF_HAND);
+        syncEquipment(EquipmentSlot.OFF_HAND);
     }
 
     @NotNull
@@ -97,8 +93,8 @@ public class EntityArmorStand extends ObjectEntity implements EquipmentHandler {
 
     @Override
     public void setHelmet(@NotNull ItemStack itemStack) {
-        this.helmet = getEquipmentItem(itemStack, ArmorEquipEvent.ArmorSlot.HELMET);
+        this.helmet = getEquipmentItem(itemStack, EquipmentSlot.HELMET);
-        syncEquipment(EntityEquipmentPacket.Slot.HELMET);
+        syncEquipment(EquipmentSlot.HELMET);
     }
 
     @NotNull
@@ -109,8 +105,8 @@ public class EntityArmorStand extends ObjectEntity implements EquipmentHandler {
 
     @Override
     public void setChestplate(@NotNull ItemStack itemStack) {
-        this.chestplate = getEquipmentItem(itemStack, ArmorEquipEvent.ArmorSlot.CHESTPLATE);
+        this.chestplate = getEquipmentItem(itemStack, EquipmentSlot.CHESTPLATE);
-        syncEquipment(EntityEquipmentPacket.Slot.CHESTPLATE);
+        syncEquipment(EquipmentSlot.CHESTPLATE);
     }
 
     @NotNull
@@ -121,8 +117,8 @@ public class EntityArmorStand extends ObjectEntity implements EquipmentHandler {
 
     @Override
     public void setLeggings(@NotNull ItemStack itemStack) {
-        this.leggings = getEquipmentItem(itemStack, ArmorEquipEvent.ArmorSlot.LEGGINGS);
+        this.leggings = getEquipmentItem(itemStack, EquipmentSlot.LEGGINGS);
-        syncEquipment(EntityEquipmentPacket.Slot.LEGGINGS);
+        syncEquipment(EquipmentSlot.LEGGINGS);
     }
 
     @NotNull
@@ -133,8 +129,8 @@ public class EntityArmorStand extends ObjectEntity implements EquipmentHandler {
 
     @Override
     public void setBoots(@NotNull ItemStack itemStack) {
-        this.boots = getEquipmentItem(itemStack, ArmorEquipEvent.ArmorSlot.BOOTS);
+        this.boots = getEquipmentItem(itemStack, EquipmentSlot.BOOTS);
-        syncEquipment(EntityEquipmentPacket.Slot.BOOTS);
+        syncEquipment(EquipmentSlot.BOOTS);
     }
 
     public boolean isSmall() {
@@ -239,9 +235,9 @@ public class EntityArmorStand extends ObjectEntity implements EquipmentHandler {
 
     // Equipments
 
-    private ItemStack getEquipmentItem(@NotNull ItemStack itemStack, @NotNull ArmorEquipEvent.ArmorSlot armorSlot) {
+    private ItemStack getEquipmentItem(@NotNull ItemStack itemStack, @NotNull EquipmentSlot slot) {
-        ArmorEquipEvent armorEquipEvent = new ArmorEquipEvent(this, itemStack, armorSlot);
+        EntityEquipEvent entityEquipEvent = new EntityEquipEvent(this, itemStack, slot);
-        callEvent(ArmorEquipEvent.class, armorEquipEvent);
+        callEvent(EntityEquipEvent.class, entityEquipEvent);
-        return armorEquipEvent.getArmorItem();
+        return entityEquipEvent.getEquippedItem();
     }
 }

src/main/java/net/minestom/server/event/handler/EventHandler.java

@@ -108,22 +108,27 @@ public interface EventHandler extends IExtensionObserver {
      */
     default <E extends Event> void callEvent(@NotNull Class<E> eventClass, @NotNull E event) {
 
-        // Global listeners
+        try {
-        if (!(this instanceof GlobalEventHandler)) {
-            final GlobalEventHandler globalEventHandler = MinecraftServer.getGlobalEventHandler();
-            runEvent(globalEventHandler.getEventCallbacks(eventClass), event);
-        }
 
-        // Local listeners
+            // Global listeners
-        final Collection<EventCallback> eventCallbacks = getEventCallbacks(eventClass);
+            if (!(this instanceof GlobalEventHandler)) {
-        runEvent(eventCallbacks, event);
+                final GlobalEventHandler globalEventHandler = MinecraftServer.getGlobalEventHandler();
-
+                runEvent(globalEventHandler.getEventCallbacks(eventClass), event);
-        // Call the same event for the current entity instance
-        if (this instanceof Entity) {
-            final Instance instance = ((Entity) this).getInstance();
-            if (instance != null) {
-                runEvent(instance.getEventCallbacks(eventClass), event);
             }
+
+            // Local listeners
+            final Collection<EventCallback> eventCallbacks = getEventCallbacks(eventClass);
+            runEvent(eventCallbacks, event);
+
+            // Call the same event for the current entity instance
+            if (this instanceof Entity) {
+                final Instance instance = ((Entity) this).getInstance();
+                if (instance != null) {
+                    runEvent(instance.getEventCallbacks(eventClass), event);
+                }
+            }
+        } catch (Exception exception) {
+            MinecraftServer.getExceptionManager().handleException(exception);
         }
     }
 

src/main/java/net/minestom/server/event/item/ArmorEquipEvent.java

@@ -1,45 +0,0 @@
-package net.minestom.server.event.item;
-
-import net.minestom.server.entity.Entity;
-import net.minestom.server.event.Event;
-import net.minestom.server.item.ItemStack;
-import org.jetbrains.annotations.NotNull;
-
-public class ArmorEquipEvent extends Event {
-
-    private final Entity entity;
-    private ItemStack armorItem;
-    private final ArmorSlot armorSlot;
-
-    public ArmorEquipEvent(@NotNull Entity entity, @NotNull ItemStack armorItem, @NotNull ArmorSlot armorSlot) {
-        this.entity = entity;
-        this.armorItem = armorItem;
-        this.armorSlot = armorSlot;
-    }
-
-    @NotNull
-    public Entity getEntity() {
-        return entity;
-    }
-
-    @NotNull
-    public ItemStack getArmorItem() {
-        return armorItem;
-    }
-
-    public void setArmorItem(@NotNull ItemStack armorItem) {
-        this.armorItem = armorItem;
-    }
-
-    @NotNull
-    public ArmorSlot getArmorSlot() {
-        return armorSlot;
-    }
-
-    public enum ArmorSlot {
-        HELMET,
-        CHESTPLATE,
-        LEGGINGS,
-        BOOTS
-    }
-}

src/main/java/net/minestom/server/event/item/EntityEquipEvent.java

@@ -0,0 +1,39 @@
+package net.minestom.server.event.item;
+
+import net.minestom.server.entity.Entity;
+import net.minestom.server.entity.EquipmentSlot;
+import net.minestom.server.event.Event;
+import net.minestom.server.item.ItemStack;
+import org.jetbrains.annotations.NotNull;
+
+public class EntityEquipEvent extends Event {
+
+    private final Entity entity;
+    private ItemStack equippedItem;
+    private final EquipmentSlot slot;
+
+    public EntityEquipEvent(@NotNull Entity entity, @NotNull ItemStack equippedItem, @NotNull EquipmentSlot slot) {
+        this.entity = entity;
+        this.equippedItem = equippedItem;
+        this.slot = slot;
+    }
+
+    @NotNull
+    public Entity getEntity() {
+        return entity;
+    }
+
+    @NotNull
+    public ItemStack getEquippedItem() {
+        return equippedItem;
+    }
+
+    public void setEquippedItem(@NotNull ItemStack armorItem) {
+        this.equippedItem = armorItem;
+    }
+
+    @NotNull
+    public EquipmentSlot getSlot() {
+        return slot;
+    }
+}

src/main/java/net/minestom/server/event/player/PlayerStartFlyingWithElytraEvent.java

@@ -0,0 +1,12 @@
+package net.minestom.server.event.player;
+
+import net.minestom.server.entity.Player;
+import net.minestom.server.event.PlayerEvent;
+import org.jetbrains.annotations.NotNull;
+
+public class PlayerStartFlyingWithElytraEvent extends PlayerEvent {
+
+    public PlayerStartFlyingWithElytraEvent(@NotNull Player player) {
+        super(player);
+    }
+}

src/main/java/net/minestom/server/event/player/PlayerStopFlyingWithElytraEvent.java

@@ -0,0 +1,12 @@
+package net.minestom.server.event.player;
+
+import net.minestom.server.entity.Player;
+import net.minestom.server.event.PlayerEvent;
+import org.jetbrains.annotations.NotNull;
+
+public class PlayerStopFlyingWithElytraEvent extends PlayerEvent {
+
+    public PlayerStopFlyingWithElytraEvent(@NotNull Player player) {
+        super(player);
+    }
+}

src/main/java/net/minestom/server/extensions/DiscoveredExtension.java

@@ -11,6 +11,7 @@ import org.slf4j.LoggerFactory;
 
 import java.io.File;
 import java.net.URL;
+import java.nio.file.Path;
 import java.util.LinkedList;
 import java.util.List;
 
@@ -75,6 +76,8 @@ public final class DiscoveredExtension {
     /** The original jar this is from. */
     transient private File originalJar;
 
+    transient private Path dataDirectory;
+
     /** The class loader that powers it. */
     transient private MinestomExtensionClassLoader minestomExtensionClassLoader;
 
@@ -130,6 +133,14 @@ public final class DiscoveredExtension {
         return originalJar;
     }
 
+    public @NotNull Path getDataDirectory() {
+        return dataDirectory;
+    }
+
+    public void setDataDirectory(@NotNull Path dataDirectory) {
+        this.dataDirectory = dataDirectory;
+    }
+
     MinestomExtensionClassLoader removeMinestomExtensionClassLoader() {
         MinestomExtensionClassLoader oldClassLoader = getMinestomExtensionClassLoader();
         setMinestomExtensionClassLoader(null);

src/main/java/net/minestom/server/extensions/Extension.java

@@ -1,11 +1,19 @@
 package net.minestom.server.extensions;
 
 import org.jetbrains.annotations.NotNull;
+import org.jetbrains.annotations.Nullable;
 import org.slf4j.Logger;
 
+import java.io.IOException;
+import java.io.InputStream;
 import java.lang.ref.Reference;
 import java.lang.ref.ReferenceQueue;
 import java.lang.ref.WeakReference;
+import java.net.URL;
+import java.nio.file.Files;
+import java.nio.file.Path;
+import java.nio.file.Paths;
+import java.nio.file.StandardCopyOption;
 import java.util.*;
 import java.util.concurrent.ConcurrentHashMap;
 import java.util.function.Consumer;
@@ -77,6 +85,118 @@ public abstract class Extension {
         return logger;
     }
 
+    public @NotNull Path getDataDirectory() {
+        return getOrigin().getDataDirectory();
+    }
+
+    /**
+     * Gets a resource from the extension directory, or from inside the jar if it does not
+     * exist in the extension directory.
+     * <p>
+     * If it does not exist in the extension directory, it will be copied from inside the jar.
+     * <p>
+     * The caller is responsible for closing the returned {@link InputStream}.
+     *
+     * @param fileName The file to read
+     * @return The file contents, or null if there was an issue reading the file.
+     */
+    public @Nullable InputStream getResource(@NotNull String fileName) {
+        return getResource(Paths.get(fileName));
+    }
+
+    /**
+     * Gets a resource from the extension directory, or from inside the jar if it does not
+     * exist in the extension directory.
+     * <p>
+     * If it does not exist in the extension directory, it will be copied from inside the jar.
+     * <p>
+     * The caller is responsible for closing the returned {@link InputStream}.
+     *
+     * @param target The file to read
+     * @return The file contents, or null if there was an issue reading the file.
+     */
+    public @Nullable InputStream getResource(@NotNull Path target) {
+        final Path targetFile = getDataDirectory().resolve(target);
+        try {
+            // Copy from jar if the file does not exist in the extension data directory.
+            if (!Files.exists(targetFile)) {
+                savePackagedResource(target);
+            }
+
+            return Files.newInputStream(targetFile);
+        } catch (IOException ex) {
+            getLogger().info("Failed to read resource {}.", target, ex);
+            return null;
+        }
+    }
+
+    /**
+     * Gets a resource from inside the extension jar.
+     * <p>
+     * The caller is responsible for closing the returned {@link InputStream}.
+     *
+     * @param fileName The file to read
+     * @return The file contents, or null if there was an issue reading the file.
+     */
+    public @Nullable InputStream getPackagedResource(@NotNull String fileName) {
+        return getPackagedResource(Paths.get(fileName));
+    }
+
+    /**
+     * Gets a resource from inside the extension jar.
+     * <p>
+     * The caller is responsible for closing the returned {@link InputStream}.
+     *
+     * @param target The file to read
+     * @return The file contents, or null if there was an issue reading the file.
+     */
+    public @Nullable InputStream getPackagedResource(@NotNull Path target) {
+        try {
+            final URL url = getOrigin().getMinestomExtensionClassLoader().getResource(target.toString());
+            if (url == null) {
+                getLogger().debug("Resource not found: {}", target);
+                return null;
+            }
+
+            return url.openConnection().getInputStream();
+        } catch (IOException ex) {
+            getLogger().debug("Failed to load resource {}.", target, ex);
+            return null;
+        }
+    }
+
+    /**
+     * Copies a resource file to the extension directory, replacing any existing copy.
+     *
+     * @param fileName The resource to save
+     * @return True if the resource was saved successfully, null otherwise
+     */
+    public boolean savePackagedResource(@NotNull String fileName) {
+        return savePackagedResource(Paths.get(fileName));
+    }
+
+    /**
+     * Copies a resource file to the extension directory, replacing any existing copy.
+     *
+     * @param target The resource to save
+     * @return True if the resource was saved successfully, null otherwise
+     */
+    public boolean savePackagedResource(@NotNull Path target) {
+        final Path targetFile = getDataDirectory().resolve(target);
+        try (InputStream is = getPackagedResource(target)) {
+            if (is == null) {
+                return false;
+            }
+
+            Files.createDirectories(targetFile.getParent());
+            Files.copy(is, targetFile, StandardCopyOption.REPLACE_EXISTING);
+            return true;
+        } catch (IOException ex) {
+            getLogger().debug("Failed to save resource {}.", target, ex);
+            return false;
+        }
+    }
+
     /**
      * Adds a new observer to this extension.
      * Will be kept as a WeakReference.

src/main/java/net/minestom/server/extensions/ExtensionManager.java

@@ -24,6 +24,8 @@ import java.lang.reflect.Constructor;
 import java.lang.reflect.Field;
 import java.lang.reflect.InvocationTargetException;
 import java.net.URL;
+import java.nio.file.Path;
+import java.nio.file.Paths;
 import java.util.*;
 import java.util.stream.Collectors;
 import java.util.zip.ZipFile;
@@ -44,6 +46,7 @@ public class ExtensionManager {
 
     private final File extensionFolder = new File("extensions");
     private final File dependenciesFolder = new File(extensionFolder, ".libs");
+    private Path extensionDataRoot = extensionFolder.toPath();
     private boolean loaded;
 
     // Option
@@ -336,6 +339,7 @@ public class ExtensionManager {
                 DiscoveredExtension extension = GSON.fromJson(reader, DiscoveredExtension.class);
                 extension.files.add(new File(extensionClasses).toURI().toURL());
                 extension.files.add(new File(extensionResources).toURI().toURL());
+                extension.setDataDirectory(getExtensionDataRoot().resolve(extension.getName()));
 
                 // Verify integrity and ensure defaults
                 DiscoveredExtension.verifyIntegrity(extension);
@@ -365,6 +369,7 @@ public class ExtensionManager {
             DiscoveredExtension extension = GSON.fromJson(reader, DiscoveredExtension.class);
             extension.setOriginalJar(file);
             extension.files.add(file.toURI().toURL());
+            extension.setDataDirectory(getExtensionDataRoot().resolve(extension.getName()));
 
             // Verify integrity and ensure defaults
             DiscoveredExtension.verifyIntegrity(extension);
@@ -569,6 +574,14 @@ public class ExtensionManager {
         return extensionFolder;
     }
 
+    public @NotNull Path getExtensionDataRoot() {
+        return extensionDataRoot;
+    }
+
+    public void setExtensionDataRoot(@NotNull Path dataRoot) {
+        this.extensionDataRoot = dataRoot;
+    }
+
     @NotNull
     public Collection<Extension> getExtensions() {
         return immutableExtensions.values();

src/main/java/net/minestom/server/extras/MojangAuth.java

@@ -1,14 +1,10 @@
 package net.minestom.server.extras;
 
-import com.mojang.authlib.AuthenticationService;
-import com.mojang.authlib.minecraft.MinecraftSessionService;
-import com.mojang.authlib.yggdrasil.YggdrasilAuthenticationService;
 import net.minestom.server.MinecraftServer;
 import net.minestom.server.extras.mojangAuth.MojangCrypt;
 import net.minestom.server.utils.validate.Check;
 import org.jetbrains.annotations.Nullable;
 
-import java.net.Proxy;
 import java.security.KeyPair;
 
 public final class MojangAuth {
@@ -16,8 +12,6 @@ public final class MojangAuth {
     private static volatile boolean enabled = false;
 
     private static KeyPair keyPair;
-    private static AuthenticationService authService;
-    private static MinecraftSessionService sessionService;
 
     /**
      * Enables mojang authentication on the server.
@@ -32,8 +26,6 @@ public final class MojangAuth {
 
         // Generate necessary fields...
         keyPair = MojangCrypt.generateKeyPair();
-        authService = new YggdrasilAuthenticationService(Proxy.NO_PROXY, "");
-        sessionService = authService.createMinecraftSessionService();
     }
 
     public static boolean isEnabled() {
@@ -44,14 +36,4 @@ public final class MojangAuth {
     public static KeyPair getKeyPair() {
         return keyPair;
     }
-
-    @Nullable
-    public static AuthenticationService getAuthService() {
-        return authService;
-    }
-
-    @Nullable
-    public static MinecraftSessionService getSessionService() {
-        return sessionService;
-    }
 }

src/main/java/net/minestom/server/instance/block/rule/vanilla/StairsPlacementRule.java

@@ -1,5 +1,6 @@
 package net.minestom.server.instance.block.rule.vanilla;
 
+import it.unimi.dsi.fastutil.Pair;
 import net.minestom.server.entity.Player;
 import net.minestom.server.instance.Instance;
 import net.minestom.server.instance.block.Block;
@@ -7,7 +8,6 @@ import net.minestom.server.instance.block.BlockAlternative;
 import net.minestom.server.instance.block.BlockFace;
 import net.minestom.server.instance.block.rule.BlockPlacementRule;
 import net.minestom.server.utils.BlockPosition;
-import org.apache.commons.lang3.tuple.Pair;
 import org.jetbrains.annotations.NotNull;
 import org.jetbrains.annotations.Nullable;
 
@@ -113,10 +113,10 @@ public class StairsPlacementRule extends BlockPlacementRule {
 
     @Nullable
     private Shape getShapeFromSide(@NotNull Pair<Shape, Facing> side, @NotNull Facing facing, @NotNull Shape right, @NotNull Shape left) {
-        if (side.getLeft() == null) {
+        if (side.left() == null) {
             return null;
         }
-        Facing sideFacing = side.getRight();
+        Facing sideFacing = side.right();
         if (facing.equals(Facing.NORTH)) {
             if (sideFacing.equals(Facing.EAST)) {
                 return right;

src/main/java/net/minestom/server/instance/palette/Section.java

@@ -53,6 +53,8 @@ public class Section implements PublicCloneable<Section> {
     private int valuesPerLong;
     private boolean hasPalette;
 
+    private short blockCount = 0;
+
     protected Section(int bitsPerEntry, int bitsIncrement) {
         this.bitsPerEntry = bitsPerEntry;
         this.bitsIncrement = bitsIncrement;
@@ -74,6 +76,9 @@ public class Section implements PublicCloneable<Section> {
             blocks = new long[getSize(valuesPerLong)];
         }
 
+        // Check if the new block is air, used for counting none air blocks.
+        final boolean isAir = Block.fromStateId(blockId).isAir();
+
         // Change to palette value
         blockId = getPaletteIndex(blockId);
 
@@ -87,10 +92,20 @@ public class Section implements PublicCloneable<Section> {
         {
             final long clear = MAGIC_MASKS[bitsPerEntry];
 
+            final long value = block >> bitIndex & clear;
+            final boolean isCurrentAir = Block.fromStateId(
+                    hasPalette ? paletteBlockMap.get((short) value) : (short) value).isAir();
+
             block |= clear << bitIndex;
             block ^= clear << bitIndex;
             block |= (long) blockId << bitIndex;
 
+            if (!isCurrentAir && isAir) { // The old block isn't air & the new block is.
+                this.blockCount--;
+            } else if (isCurrentAir && !isAir) { // The old block is air & the new block isn't.
+                this.blockCount++;
+            } // If both block are air or not air then don't change the value.
+
             blocks[index] = block;
         }
     }
@@ -143,6 +158,7 @@ public class Section implements PublicCloneable<Section> {
         this.hasPalette = section.hasPalette;
 
         this.blocks = section.blocks;
+        this.blockCount = section.blockCount;
     }
 
     /**
@@ -171,12 +187,22 @@ public class Section implements PublicCloneable<Section> {
         this.blocks = new long[0];
         this.paletteBlockMap = createPaletteBlockMap();
         this.blockPaletteMap = createBlockPaletteMap();
+        this.blockCount = 0;
     }
 
     public long[] getBlocks() {
         return blocks;
     }
 
+    /**
+     * Get the amount of non air blocks in this section.
+     *
+     * @return The amount of blocks in this section.
+     */
+    public short getBlockCount() {
+        return blockCount;
+    }
+
     public Short2ShortLinkedOpenHashMap getPaletteBlockMap() {
         return paletteBlockMap;
     }
@@ -288,6 +314,7 @@ public class Section implements PublicCloneable<Section> {
             section.blocks = blocks.clone();
             section.paletteBlockMap = paletteBlockMap.clone();
             section.blockPaletteMap = blockPaletteMap.clone();
+            section.blockCount = blockCount;
             return section;
         } catch (CloneNotSupportedException e) {
             MinecraftServer.getExceptionManager().handleException(e);

src/main/java/net/minestom/server/inventory/EquipmentHandler.java

@@ -1,6 +1,7 @@
 package net.minestom.server.inventory;
 
 import net.minestom.server.entity.Entity;
+import net.minestom.server.entity.EquipmentSlot;
 import net.minestom.server.entity.Player;
 import net.minestom.server.item.ItemStack;
 import net.minestom.server.network.packet.server.play.EntityEquipmentPacket;
@@ -139,7 +140,7 @@ public interface EquipmentHandler {
      * @param slot the equipment to get the item from
      * @return the equipment {@link ItemStack}
      */
-    default @NotNull ItemStack getEquipment(@NotNull EntityEquipmentPacket.Slot slot) {
+    default @NotNull ItemStack getEquipment(@NotNull EquipmentSlot slot) {
         switch (slot) {
             case MAIN_HAND:
                 return getItemInMainHand();
@@ -157,7 +158,7 @@ public interface EquipmentHandler {
         throw new IllegalStateException("Something weird happened");
     }
 
-    default void setEquipment(@NotNull EntityEquipmentPacket.Slot slot, @NotNull ItemStack itemStack) {
+    default void setEquipment(@NotNull EquipmentSlot slot, @NotNull ItemStack itemStack) {
         switch (slot) {
             case MAIN_HAND:
                 setItemInMainHand(itemStack);
@@ -187,7 +188,7 @@ public interface EquipmentHandler {
      *
      * @param slot the slot of the equipment
      */
-    default void syncEquipment(@NotNull EntityEquipmentPacket.Slot slot) {
+    default void syncEquipment(@NotNull EquipmentSlot slot) {
         Check.stateCondition(!(this instanceof Entity), "Only accessible for Entity");
 
         Entity entity = (Entity) this;
@@ -196,7 +197,7 @@ public interface EquipmentHandler {
 
         EntityEquipmentPacket entityEquipmentPacket = new EntityEquipmentPacket();
         entityEquipmentPacket.entityId = entity.getEntityId();
-        entityEquipmentPacket.slots = new EntityEquipmentPacket.Slot[]{slot};
+        entityEquipmentPacket.slots = new EquipmentSlot[]{slot};
         entityEquipmentPacket.itemStacks = new ItemStack[]{itemStack};
 
         entity.sendPacketToViewers(entityEquipmentPacket);
@@ -213,12 +214,12 @@ public interface EquipmentHandler {
 
         final Entity entity = (Entity) this;
 
-        final EntityEquipmentPacket.Slot[] slots = EntityEquipmentPacket.Slot.values();
+        final EquipmentSlot[] slots = EquipmentSlot.values();
 
         List<ItemStack> itemStacks = new ArrayList<>(slots.length);
 
         // Fill items
-        for (EntityEquipmentPacket.Slot slot : slots) {
+        for (EquipmentSlot slot : slots) {
             final ItemStack equipment = getEquipment(slot);
             itemStacks.add(equipment);
         }

src/main/java/net/minestom/server/inventory/PlayerInventory.java

@@ -1,12 +1,12 @@
 package net.minestom.server.inventory;
 
+import net.minestom.server.entity.EquipmentSlot;
 import net.minestom.server.entity.Player;
-import net.minestom.server.event.item.ArmorEquipEvent;
+import net.minestom.server.event.item.EntityEquipEvent;
 import net.minestom.server.inventory.click.ClickType;
 import net.minestom.server.inventory.click.InventoryClickResult;
 import net.minestom.server.inventory.condition.InventoryCondition;
 import net.minestom.server.item.ItemStack;
-import net.minestom.server.network.packet.server.play.EntityEquipmentPacket;
 import net.minestom.server.network.packet.server.play.SetSlotPacket;
 import net.minestom.server.network.packet.server.play.WindowItemsPacket;
 import net.minestom.server.utils.MathUtils;
@@ -170,33 +170,27 @@ public class PlayerInventory extends AbstractInventory implements EquipmentHandl
                 "The slot {0} does not exist for player", slot);
         Check.notNull(itemStack, "The ItemStack cannot be null, you can set air instead");
 
-        EntityEquipmentPacket.Slot equipmentSlot;
+        EquipmentSlot equipmentSlot = null;
 
         if (slot == player.getHeldSlot()) {
-            equipmentSlot = EntityEquipmentPacket.Slot.MAIN_HAND;
+            equipmentSlot = EquipmentSlot.MAIN_HAND;
         } else if (slot == OFFHAND_SLOT) {
-            equipmentSlot = EntityEquipmentPacket.Slot.OFF_HAND;
+            equipmentSlot = EquipmentSlot.OFF_HAND;
-        } else {
+        } else if (slot == HELMET_SLOT) {
-            ArmorEquipEvent armorEquipEvent = null;
+            equipmentSlot = EquipmentSlot.HELMET;
+        } else if (slot == CHESTPLATE_SLOT) {
+            equipmentSlot = EquipmentSlot.CHESTPLATE;
+        } else if (slot == LEGGINGS_SLOT) {
+            equipmentSlot = EquipmentSlot.LEGGINGS;
+        } else if (slot == BOOTS_SLOT) {
+            equipmentSlot = EquipmentSlot.BOOTS;
+        }
 
-            if (slot == HELMET_SLOT) {
+        if (equipmentSlot != null) {
-                armorEquipEvent = new ArmorEquipEvent(player, itemStack, ArmorEquipEvent.ArmorSlot.HELMET);
+            EntityEquipEvent entityEquipEvent = new EntityEquipEvent(player, itemStack, equipmentSlot);
-            } else if (slot == CHESTPLATE_SLOT) {
-                armorEquipEvent = new ArmorEquipEvent(player, itemStack, ArmorEquipEvent.ArmorSlot.CHESTPLATE);
-            } else if (slot == LEGGINGS_SLOT) {
-                armorEquipEvent = new ArmorEquipEvent(player, itemStack, ArmorEquipEvent.ArmorSlot.LEGGINGS);
-            } else if (slot == BOOTS_SLOT) {
-                armorEquipEvent = new ArmorEquipEvent(player, itemStack, ArmorEquipEvent.ArmorSlot.BOOTS);
-            }
 
-            if (armorEquipEvent != null) {
+            player.callEvent(EntityEquipEvent.class, entityEquipEvent);
-                ArmorEquipEvent.ArmorSlot armorSlot = armorEquipEvent.getArmorSlot();
+            itemStack = entityEquipEvent.getEquippedItem();
-                equipmentSlot = EntityEquipmentPacket.Slot.fromArmorSlot(armorSlot);
-                player.callEvent(ArmorEquipEvent.class, armorEquipEvent);
-                itemStack = armorEquipEvent.getArmorItem();
-            } else {
-                equipmentSlot = null;
-            }
         }
 
         this.itemStacks[slot] = itemStack;

src/main/java/net/minestom/server/inventory/type/VillagerInventory.java

@@ -1,9 +1,11 @@
 package net.minestom.server.inventory.type;
 
+import net.minestom.server.entity.Player;
 import net.minestom.server.inventory.Inventory;
 import net.minestom.server.inventory.InventoryType;
 import net.minestom.server.network.packet.server.play.TradeListPacket;
 import net.minestom.server.utils.ArrayUtils;
+import org.jetbrains.annotations.NotNull;
 
 public class VillagerInventory extends Inventory {
 
@@ -23,7 +25,7 @@ public class VillagerInventory extends Inventory {
         final int length = oldTrades.length + 1;
         TradeListPacket.Trade[] trades = new TradeListPacket.Trade[length];
         System.arraycopy(oldTrades, 0, trades, 0, oldTrades.length);
-        trades[length] = trade;
+        trades[length - 1] = trade;
         this.tradeListPacket.trades = trades;
         update();
     }
@@ -79,6 +81,15 @@ public class VillagerInventory extends Inventory {
         sendPacketToViewers(tradeListPacket); // Refresh window
     }
 
+    @Override
+    public boolean addViewer(@NotNull Player player) {
+        final boolean result = super.addViewer(player);
+        if (result) {
+            player.getPlayerConnection().sendPacket(tradeListPacket);
+        }
+        return result;
+    }
+
     private void setupPacket() {
         this.tradeListPacket = new TradeListPacket();
         this.tradeListPacket.windowId = getWindowId();

src/main/java/net/minestom/server/item/ItemMeta.java

@@ -4,6 +4,8 @@ import io.netty.buffer.ByteBuf;
 import net.kyori.adventure.text.Component;
 import net.minestom.server.instance.block.Block;
 import net.minestom.server.item.attribute.ItemAttribute;
+import net.minestom.server.tag.Tag;
+import net.minestom.server.tag.TagReadable;
 import net.minestom.server.utils.binary.BinaryWriter;
 import net.minestom.server.utils.binary.Writeable;
 import org.jetbrains.annotations.Contract;
@@ -13,8 +15,9 @@ import org.jglrxavpok.hephaistos.nbt.NBTCompound;
 
 import java.util.*;
 import java.util.function.Consumer;
+import java.util.function.Supplier;
 
-public class ItemMeta implements Writeable {
+public class ItemMeta implements TagReadable, Writeable {
 
     private final int damage;
     private final boolean unbreakable;
@@ -109,18 +112,14 @@ public class ItemMeta implements Writeable {
         return Collections.unmodifiableSet(canPlaceOn);
     }
 
-    @Contract(pure = true)
+    @Override
-    public <T> T getOrDefault(@NotNull ItemTag<T> tag, @Nullable T defaultValue) {
+    public <T> @Nullable T getTag(@NotNull Tag<T> tag) {
-        var key = tag.getKey();
+        return tag.read(nbt);
-        if (nbt.containsKey(key)) {
-            return tag.read(toNBT());
-        } else {
-            return defaultValue;
-        }
     }
 
-    public <T> @Nullable T get(@NotNull ItemTag<T> tag) {
+    @Override
-        return tag.read(toNBT());
+    public boolean hasTag(@NotNull Tag<?> tag) {
+        return nbt.containsKey(tag.getKey());
     }
 
     public @NotNull NBTCompound toNBT() {
@@ -163,4 +162,26 @@ public class ItemMeta implements Writeable {
         writer.write(cachedBuffer);
         this.cachedBuffer.resetReaderIndex();
     }
+
+    /**
+     * @deprecated use {@link #getTag(Tag)} with {@link Tag#defaultValue(Supplier)}
+     */
+    @Deprecated
+    @Contract(pure = true)
+    public <T> T getOrDefault(@NotNull Tag<T> tag, @Nullable T defaultValue) {
+        var key = tag.getKey();
+        if (nbt.containsKey(key)) {
+            return tag.read(toNBT());
+        } else {
+            return defaultValue;
+        }
+    }
+
+    /**
+     * @deprecated use {@link #getTag(Tag)}
+     */
+    @Deprecated
+    public <T> @Nullable T get(@NotNull Tag<T> tag) {
+        return getTag(tag);
+    }
 }

src/main/java/net/minestom/server/item/ItemMetaBuilder.java

@@ -5,6 +5,8 @@ import net.kyori.adventure.text.serializer.gson.GsonComponentSerializer;
 import net.minestom.server.adventure.AdventureSerializer;
 import net.minestom.server.instance.block.Block;
 import net.minestom.server.item.attribute.ItemAttribute;
+import net.minestom.server.tag.Tag;
+import net.minestom.server.tag.TagWritable;
 import net.minestom.server.utils.NBTUtils;
 import net.minestom.server.utils.Utils;
 import org.jetbrains.annotations.Contract;
@@ -16,7 +18,7 @@ import java.util.*;
 import java.util.function.Consumer;
 import java.util.function.Supplier;
 
-public abstract class ItemMetaBuilder {
+public abstract class ItemMetaBuilder implements TagWritable {
 
     protected NBTCompound nbt = new NBTCompound();
 
@@ -183,12 +185,13 @@ public abstract class ItemMetaBuilder {
         return canDestroy(Set.of(blocks));
     }
 
-    public <T> @NotNull ItemMetaBuilder set(@NotNull ItemTag<T> tag, @Nullable T value) {
+    @Override
-        if (value != null) {
+    public <T> void setTag(@NotNull Tag<T> tag, @Nullable T value) {
-            tag.write(nbt, value);
+        tag.write(nbt, value);
-        } else {
+    }
-            this.nbt.removeTag(tag.getKey());
+
-        }
+    public <T> @NotNull ItemMetaBuilder set(@NotNull Tag<T> tag, @Nullable T value) {
+        setTag(tag, value);
         return this;
     }
 

src/main/java/net/minestom/server/item/ItemStack.java

@@ -4,6 +4,8 @@ import net.kyori.adventure.text.Component;
 import net.kyori.adventure.text.event.HoverEvent;
 import net.kyori.adventure.text.event.HoverEventSource;
 import net.minestom.server.item.rule.VanillaStackingRule;
+import net.minestom.server.tag.Tag;
+import net.minestom.server.tag.TagReadable;
 import net.minestom.server.utils.NBTUtils;
 import org.jetbrains.annotations.Contract;
 import org.jetbrains.annotations.NotNull;
@@ -22,7 +24,7 @@ import java.util.function.UnaryOperator;
  * <p>
  * An item stack cannot be null, {@link ItemStack#AIR} should be used instead.
  */
-public final class ItemStack implements HoverEventSource<HoverEvent.ShowItem> {
+public final class ItemStack implements TagReadable, HoverEventSource<HoverEvent.ShowItem> {
 
     /**
      * Constant AIR item. Should be used instead of 'null'.
@@ -191,6 +193,21 @@ public final class ItemStack implements HoverEventSource<HoverEvent.ShowItem> {
                 .stackingRule(stackingRule);
     }
 
+    @Contract(value = "_, _ -> new", pure = true)
+    public <T> @NotNull ItemStack withTag(@NotNull Tag<T> tag, @Nullable T value) {
+        return builder().meta(metaBuilder -> metaBuilder.set(tag, value)).build();
+    }
+
+    @Override
+    public <T> @Nullable T getTag(@NotNull Tag<T> tag) {
+        return meta.getTag(tag);
+    }
+
+    @Override
+    public boolean hasTag(@NotNull Tag<?> tag) {
+        return meta.hasTag(tag);
+    }
+
     @Override
     public @NotNull HoverEvent<HoverEvent.ShowItem> asHoverEvent(@NotNull UnaryOperator<HoverEvent.ShowItem> op) {
         return HoverEvent.showItem(op.apply(HoverEvent.ShowItem.of(this.material,

src/main/java/net/minestom/server/item/ItemTag.java

@@ -1,112 +1,65 @@
 package net.minestom.server.item;
 
+import net.minestom.server.tag.Tag;
 import org.jetbrains.annotations.NotNull;
 import org.jglrxavpok.hephaistos.nbt.NBT;
 import org.jglrxavpok.hephaistos.nbt.NBTCompound;
-import org.jglrxavpok.hephaistos.nbt.NBTList;
 
 import java.util.function.BiConsumer;
 import java.util.function.Function;
 
-public class ItemTag<T> {
+/**
+ * @deprecated use {@link Tag}.
+ */
+@Deprecated
+public class ItemTag<T> extends Tag<T> {
 
-    private final String key;
+    protected ItemTag(@NotNull String key, @NotNull Function<NBTCompound, T> readFunction, @NotNull BiConsumer<NBTCompound, T> writeConsumer) {
-    private final Function<NBTCompound, T> readFunction;
+        super(key, readFunction, writeConsumer);
-    private final BiConsumer<NBTCompound, T> writeConsumer;
-
-    private ItemTag(@NotNull String key,
-                    @NotNull Function<NBTCompound, T> readFunction,
-                    @NotNull BiConsumer<NBTCompound, T> writeConsumer) {
-        this.key = key;
-        this.readFunction = readFunction;
-        this.writeConsumer = writeConsumer;
     }
 
-    public @NotNull String getKey() {
+    public static @NotNull Tag<Byte> Byte(@NotNull String key) {
-        return key;
+        return Tag.Byte(key);
     }
 
-    protected T read(@NotNull NBTCompound nbtCompound) {
+    public static @NotNull Tag<Short> Short(@NotNull String key) {
-        return readFunction.apply(nbtCompound);
+        return Tag.Short(key);
     }
 
-    protected void write(@NotNull NBTCompound nbtCompound, @NotNull T value) {
+    public static @NotNull Tag<Integer> Integer(@NotNull String key) {
-        this.writeConsumer.accept(nbtCompound, value);
+        return Tag.Integer(key);
     }
 
-    public static @NotNull ItemTag<Byte> Byte(@NotNull String key) {
+    public static @NotNull Tag<Long> Long(@NotNull String key) {
-        return new ItemTag<>(key,
+        return Tag.Long(key);
-                nbtCompound -> nbtCompound.getByte(key),
-                (nbtCompound, value) -> nbtCompound.setByte(key, value));
     }
 
-    public static @NotNull ItemTag<Short> Short(@NotNull String key) {
+    public static @NotNull Tag<Float> Float(@NotNull String key) {
-        return new ItemTag<>(key,
+        return Tag.Float(key);
-                nbtCompound -> nbtCompound.getShort(key),
-                (nbtCompound, value) -> nbtCompound.setShort(key, value));
     }
 
-    public static @NotNull ItemTag<Integer> Integer(@NotNull String key) {
+    public static @NotNull Tag<Double> Double(@NotNull String key) {
-        return new ItemTag<>(key,
+        return Tag.Double(key);
-                nbtCompound -> nbtCompound.getInt(key),
-                (nbtCompound, integer) -> nbtCompound.setInt(key, integer));
     }
 
-    public static @NotNull ItemTag<Long> Long(@NotNull String key) {
+    public static @NotNull Tag<byte[]> ByteArray(@NotNull String key) {
-        return new ItemTag<>(key,
+        return Tag.ByteArray(key);
-                nbtCompound -> nbtCompound.getLong(key),
-                (nbtCompound, value) -> nbtCompound.setLong(key, value));
     }
 
-    public static @NotNull ItemTag<Float> Float(@NotNull String key) {
+    public static @NotNull Tag<String> String(@NotNull String key) {
-        return new ItemTag<>(key,
+        return Tag.String(key);
-                nbtCompound -> nbtCompound.getFloat(key),
-                (nbtCompound, value) -> nbtCompound.setFloat(key, value));
     }
 
-    public static @NotNull ItemTag<Double> Double(@NotNull String key) {
+    public static @NotNull Tag<NBT> NBT(@NotNull String key) {
-        return new ItemTag<>(key,
+        return Tag.NBT(key);
-                nbtCompound -> nbtCompound.getDouble(key),
-                (nbtCompound, value) -> nbtCompound.setDouble(key, value));
     }
 
-    public static @NotNull ItemTag<byte[]> ByteArray(@NotNull String key) {
+    public static @NotNull Tag<int[]> IntArray(@NotNull String key) {
-        return new ItemTag<>(key,
+        return Tag.IntArray(key);
-                nbtCompound -> nbtCompound.getByteArray(key),
-                (nbtCompound, value) -> nbtCompound.setByteArray(key, value));
     }
 
-    public static @NotNull ItemTag<String> String(@NotNull String key) {
+    public static @NotNull Tag<long[]> LongArray(@NotNull String key) {
-        return new ItemTag<>(key,
+        return Tag.LongArray(key);
-                nbtCompound -> nbtCompound.getString(key),
-                (nbtCompound, value) -> nbtCompound.setString(key, value));
-    }
-
-    public static @NotNull ItemTag<NBT> NBT(@NotNull String key) {
-        return new ItemTag<>(key,
-                nbt -> {
-                    var currentNBT = nbt.get(key);
-
-                    // Avoid a NPE when cloning a null variable.
-                    if (currentNBT == null) {
-                        return null;
-                    }
-
-                    return currentNBT.deepClone();
-                },
-                ((nbt, value) -> nbt.set(key, value.deepClone())));
-    }
-
-    public static @NotNull ItemTag<int[]> IntArray(@NotNull String key) {
-        return new ItemTag<>(key,
-                nbtCompound -> nbtCompound.getIntArray(key),
-                (nbtCompound, value) -> nbtCompound.setIntArray(key, value));
-    }
-
-    public static @NotNull ItemTag<long[]> LongArray(@NotNull String key) {
-        return new ItemTag<>(key,
-                nbtCompound -> nbtCompound.getLongArray(key),
-                (nbtCompound, value) -> nbtCompound.setLongArray(key, value));
     }
 
 }

src/main/java/net/minestom/server/listener/ChatMessageListener.java

@@ -6,10 +6,10 @@ import net.minestom.server.MinecraftServer;
 import net.minestom.server.command.CommandManager;
 import net.minestom.server.entity.Player;
 import net.minestom.server.event.player.PlayerChatEvent;
+import net.minestom.server.message.ChatPosition;
+import net.minestom.server.message.Messenger;
 import net.minestom.server.network.ConnectionManager;
 import net.minestom.server.network.packet.client.play.ClientChatMessagePacket;
-import net.minestom.server.network.packet.server.play.ChatMessagePacket;
-import net.minestom.server.utils.PacketUtils;
 import org.jetbrains.annotations.NotNull;
 
 import java.util.Collection;
@@ -26,21 +26,30 @@ public class ChatMessageListener {
         final String cmdPrefix = CommandManager.COMMAND_PREFIX;
         if (message.startsWith(cmdPrefix)) {
             // The message is a command
-            message = message.replaceFirst(cmdPrefix, "");
+            final String command = message.replaceFirst(cmdPrefix, "");
 
-            COMMAND_MANAGER.execute(player, message);
+            // check if we can receive commands
+            if (Messenger.canReceiveCommand(player)) {
+                COMMAND_MANAGER.execute(player, command);
+            } else {
+                Messenger.sendRejectionMessage(player);
+            }
 
             // Do not call chat event
             return;
         }
 
+        // check if we can receive messages
+        if (!Messenger.canReceiveMessage(player)) {
+            Messenger.sendRejectionMessage(player);
+            return;
+        }
+
         final Collection<Player> players = CONNECTION_MANAGER.getOnlinePlayers();
-        String finalMessage = message;
+        PlayerChatEvent playerChatEvent = new PlayerChatEvent(player, players, () -> buildDefaultChatMessage(player, message), message);
-        PlayerChatEvent playerChatEvent = new PlayerChatEvent(player, players, () -> buildDefaultChatMessage(player, finalMessage), message);
 
         // Call the event
         player.callCancellableEvent(PlayerChatEvent.class, playerChatEvent, () -> {
-
             final Function<PlayerChatEvent, Component> formatFunction = playerChatEvent.getChatFormatFunction();
 
             Component textObject;
@@ -55,15 +64,10 @@ public class ChatMessageListener {
 
             final Collection<Player> recipients = playerChatEvent.getRecipients();
             if (!recipients.isEmpty()) {
-                // Send the message with the correct player UUID
+                // delegate to the messenger to avoid sending messages we shouldn't be
-                ChatMessagePacket chatMessagePacket =
+                Messenger.sendMessage(recipients, textObject, ChatPosition.CHAT, player.getUuid());
-                        new ChatMessagePacket(textObject, ChatMessagePacket.Position.CHAT, player.getUuid());
-
-                PacketUtils.sendGroupedPacket(recipients, chatMessagePacket);
             }
-
         });
-
     }
 
     private static @NotNull Component buildDefaultChatMessage(@NotNull Player player, @NotNull String message) {

src/main/java/net/minestom/server/listener/EntityActionListener.java

@@ -1,10 +1,7 @@
 package net.minestom.server.listener;
 
 import net.minestom.server.entity.Player;
-import net.minestom.server.event.player.PlayerStartSneakingEvent;
+import net.minestom.server.event.player.*;
-import net.minestom.server.event.player.PlayerStartSprintingEvent;
-import net.minestom.server.event.player.PlayerStopSneakingEvent;
-import net.minestom.server.event.player.PlayerStopSprintingEvent;
 import net.minestom.server.network.packet.client.play.ClientEntityActionPacket;
 
 public class EntityActionListener {
@@ -24,6 +21,9 @@ public class EntityActionListener {
             case STOP_SPRINTING:
                 EntityActionListener.setSprinting(player, false);
                 break;
+            case START_FLYING_ELYTRA:
+                EntityActionListener.startFlyingElytra(player);
+                break;
             // TODO do remaining actions
         }
     }
@@ -55,4 +55,9 @@ public class EntityActionListener {
             }
         }
     }
+
+    private static void startFlyingElytra(Player player) {
+        player.setFlyingWithElytra(true);
+        player.callEvent(PlayerStartFlyingWithElytraEvent.class, new PlayerStartFlyingWithElytraEvent(player));
+    }
 }

src/main/java/net/minestom/server/listener/SettingsListener.java

@@ -8,7 +8,7 @@ public class SettingsListener {
 
     public static void listener(ClientSettingsPacket packet, Player player) {
         Player.PlayerSettings settings = player.getSettings();
-        settings.refresh(packet.locale, packet.viewDistance, packet.chatMode, packet.chatColors, packet.displayedSkinParts, packet.mainHand);
+        settings.refresh(packet.locale, packet.viewDistance, packet.chatMessageType, packet.chatColors, packet.displayedSkinParts, packet.mainHand);
 
         PlayerSettingsChangeEvent playerSettingsChangeEvent = new PlayerSettingsChangeEvent(player);
         player.callEvent(PlayerSettingsChangeEvent.class, playerSettingsChangeEvent);

src/main/java/net/minestom/server/listener/TabCompleteListener.java

@@ -11,9 +11,10 @@ import net.minestom.server.command.builder.suggestion.SuggestionCallback;
 import net.minestom.server.entity.Player;
 import net.minestom.server.network.packet.client.play.ClientTabCompletePacket;
 import net.minestom.server.network.packet.server.play.TabCompletePacket;
-import org.apache.commons.lang3.StringUtils;
+import net.minestom.server.utils.StringUtils;
 
 import java.util.Arrays;
+import java.util.regex.Pattern;
 
 public class TabCompleteListener {
 
@@ -23,8 +24,7 @@ public class TabCompleteListener {
         String commandString = packet.text.replaceFirst(CommandManager.COMMAND_PREFIX, "");
         String[] split = commandString.split(StringUtils.SPACE);
         String commandName = split[0];
-
+        String args = commandString.replaceFirst(Pattern.quote(commandName), "");
-        String args = commandString.replaceFirst(commandName, "");
 
         final CommandQueryResult commandQueryResult = CommandParser.findCommand(commandString);
         if (commandQueryResult == null) {
@@ -48,7 +48,7 @@ public class TabCompleteListener {
             final int inputLength = input.length();
 
             final int commandLength = Arrays.stream(split).map(String::length).reduce(0, Integer::sum) +
-                    StringUtils.countMatches(args, StringUtils.SPACE);
+                    StringUtils.countMatches(args, StringUtils.SPACE_CHAR);
             final int trailingSpaces = !input.isEmpty() ? text.length() - text.trim().length() : 0;
 
             final int start = commandLength - inputLength + 1 - trailingSpaces;

src/main/java/net/minestom/server/listener/manager/PacketListenerManager.java

@@ -84,7 +84,12 @@ public final class PacketListenerManager {
 
         // Finally execute the listener
         if (packetListenerConsumer != null) {
-            packetListenerConsumer.accept(packet, player);
+            try {
+                packetListenerConsumer.accept(packet, player);
+            } catch (Exception e) {
+                // Packet is likely invalid
+                MinecraftServer.getExceptionManager().handleException(e);
+            }
         }
     }
 

src/main/java/net/minestom/server/message/ChatMessageType.java

@@ -0,0 +1,65 @@
+package net.minestom.server.message;
+
+import org.jetbrains.annotations.NotNull;
+
+import java.util.EnumSet;
+
+/**
+ * The messages that a player is willing to receive.
+ */
+public enum ChatMessageType {
+    /**
+     * The client wants all chat messages.
+     */
+    FULL(EnumSet.allOf(ChatPosition.class)),
+
+    /**
+     * The client only wants messages from commands, or system messages.
+     */
+    SYSTEM(EnumSet.of(ChatPosition.SYSTEM_MESSAGE, ChatPosition.GAME_INFO)),
+
+    /**
+     * The client doesn't want any messages.
+     */
+    NONE(EnumSet.of(ChatPosition.GAME_INFO));
+
+    private final EnumSet<ChatPosition> acceptedPositions;
+
+    ChatMessageType(@NotNull EnumSet<ChatPosition> acceptedPositions) {
+        this.acceptedPositions = acceptedPositions;
+    }
+
+    /**
+     * Checks if this message type is accepting of messages from a given position.
+     *
+     * @param chatPosition the position
+     * @return if the message is accepted
+     */
+    public boolean accepts(@NotNull ChatPosition chatPosition) {
+        return this.acceptedPositions.contains(chatPosition);
+    }
+
+    /**
+     * Gets the packet ID for this chat message type.
+     *
+     * @return the packet ID
+     */
+    public int getPacketID() {
+        return this.ordinal();
+    }
+
+    /**
+     * Gets a chat message type from a packet ID.
+     *
+     * @param id the packet ID
+     * @return the chat message type
+     */
+    public static @NotNull ChatMessageType fromPacketID(int id) {
+        switch (id) {
+            case 0: return FULL;
+            case 1: return SYSTEM;
+            case 2: return NONE;
+            default: throw new IllegalArgumentException("id must be between 0-2 (inclusive)");
+        }
+    }
+}

src/main/java/net/minestom/server/message/ChatPosition.java

@@ -0,0 +1,79 @@
+package net.minestom.server.message;
+
+import net.kyori.adventure.audience.MessageType;
+import org.jetbrains.annotations.NotNull;
+import org.jetbrains.annotations.Nullable;
+
+/**
+ * The different positions for chat messages.
+ */
+public enum ChatPosition {
+    /**
+     * A player-initiated chat message.
+     */
+    CHAT(MessageType.CHAT),
+
+    /**
+     * Feedback from running a command or other system messages.
+     */
+    SYSTEM_MESSAGE(MessageType.SYSTEM),
+
+    /**
+     * Game state information displayed above the hot bar.
+     */
+    GAME_INFO(null);
+
+    private final MessageType messageType;
+
+    ChatPosition(@NotNull MessageType messageType) {
+        this.messageType = messageType;
+    }
+
+    /**
+     * Gets the Adventure message type from this position. Note that there is no
+     * message type for {@link #GAME_INFO}, as Adventure uses the title methods for this.
+     *
+     * @return the message type, if any
+     */
+    public @Nullable MessageType getMessageType() {
+        return this.messageType;
+    }
+
+    /**
+     * Gets the packet ID of this chat position.
+     *
+     * @return the ID
+     */
+    public byte getID() {
+        return (byte) this.ordinal();
+    }
+
+    /**
+     * Gets a position from an Adventure message type.
+     *
+     * @param messageType the message type
+     * @return the position
+     */
+    public static @NotNull ChatPosition fromMessageType(@NotNull MessageType messageType) {
+        switch (messageType) {
+            case CHAT: return CHAT;
+            case SYSTEM: return SYSTEM_MESSAGE;
+        }
+        throw new IllegalArgumentException("Cannot get position from message type!");
+    }
+
+    /**
+     * Gets a position from a packet ID.
+     *
+     * @param id the id
+     * @return the chat position
+     */
+    public static @NotNull ChatPosition fromPacketID(byte id) {
+        switch (id) {
+            case 0: return CHAT;
+            case 1: return SYSTEM_MESSAGE;
+            case 2: return GAME_INFO;
+            default: throw new IllegalArgumentException("id must be between 0-2 (inclusive)");
+        }
+    }
+}

src/main/java/net/minestom/server/message/Messenger.java

@@ -0,0 +1,94 @@
+package net.minestom.server.message;
+
+import java.util.*;
+
+import net.kyori.adventure.text.Component;
+import net.kyori.adventure.text.format.NamedTextColor;
+import net.minestom.server.entity.Player;
+import net.minestom.server.network.packet.server.play.ChatMessagePacket;
+import net.minestom.server.utils.PacketUtils;
+import org.jetbrains.annotations.NotNull;
+import org.jetbrains.annotations.Nullable;
+
+/**
+ * Utility class to handle client chat settings.
+ */
+public class Messenger {
+    /**
+     * The message sent to the client if they send a chat message but it is rejected by the server.
+     */
+    public static final Component CANNOT_SEND_MESSAGE = Component.translatable("chat.cannotSend", NamedTextColor.RED);
+
+    private static final ChatMessagePacket CANNOT_SEND_PACKET = new ChatMessagePacket(CANNOT_SEND_MESSAGE, ChatPosition.SYSTEM_MESSAGE, null);
+
+    /**
+     * Sends a message to a player, respecting their chat settings.
+     *
+     * @param player the player
+     * @param message the message
+     * @param position the position
+     * @param uuid the UUID of the sender, if any
+     * @return if the message was sent
+     */
+    public static boolean sendMessage(@NotNull Player player, @NotNull Component message, @NotNull ChatPosition position, @Nullable UUID uuid) {
+        if (getChatMessageType(player).accepts(position)) {
+            player.getPlayerConnection().sendPacket(new ChatMessagePacket(message, position, uuid));
+            return true;
+        }
+
+        return false;
+    }
+
+    /**
+     * Sends a message to some players, respecting their chat settings.
+     *
+     * @param players the players
+     * @param message the message
+     * @param position the position
+     * @param uuid the UUID of the sender, if any
+     */
+    public static void sendMessage(@NotNull Collection<Player> players, @NotNull Component message,
+                                                   @NotNull ChatPosition position, @Nullable UUID uuid) {
+        PacketUtils.sendGroupedPacket(players, new ChatMessagePacket(message, position, uuid),
+                player -> getChatMessageType(player).accepts(position));
+    }
+
+    /**
+     * Checks if the server should receive messages from a player, given their chat settings.
+     *
+     * @param player the player
+     * @return if the server should receive messages from them
+     */
+    public static boolean canReceiveMessage(@NotNull Player player) {
+        return getChatMessageType(player) == ChatMessageType.FULL;
+    }
+
+    /**
+     * Checks if the server should receive commands from a player, given their chat settings.
+     *
+     * @param player the player
+     * @return if the server should receive commands from them
+     */
+    public static boolean canReceiveCommand(@NotNull Player player) {
+        return getChatMessageType(player) != ChatMessageType.NONE;
+    }
+
+    /**
+     * Sends a message to the player informing them we are rejecting their message or command.
+     *
+     * @param player the player
+     */
+    public static void sendRejectionMessage(@NotNull Player player) {
+        player.getPlayerConnection().sendPacket(CANNOT_SEND_PACKET, false);
+    }
+
+    /**
+     * Gets the chat message type for a player, returning {@link ChatMessageType#FULL} if not set.
+     *
+     * @param player the player
+     * @return the chat message type
+     */
+    private static @NotNull ChatMessageType getChatMessageType(@NotNull Player player) {
+        return Objects.requireNonNullElse(player.getSettings().getChatMessageType(), ChatMessageType.FULL);
+    }
+}

src/main/java/net/minestom/server/network/ConnectionManager.java

@@ -20,10 +20,10 @@ import net.minestom.server.network.packet.server.play.DisconnectPacket;
 import net.minestom.server.network.packet.server.play.KeepAlivePacket;
 import net.minestom.server.network.player.NettyPlayerConnection;
 import net.minestom.server.network.player.PlayerConnection;
+import net.minestom.server.utils.StringUtils;
 import net.minestom.server.utils.async.AsyncUtils;
 import net.minestom.server.utils.callback.validator.PlayerValidator;
 import net.minestom.server.utils.validate.Check;
-import org.apache.commons.text.similarity.JaroWinklerDistance;
 import org.jetbrains.annotations.NotNull;
 import org.jetbrains.annotations.Nullable;
 
@@ -33,6 +33,7 @@ import java.util.concurrent.ConcurrentLinkedQueue;
 import java.util.concurrent.CopyOnWriteArrayList;
 import java.util.concurrent.CopyOnWriteArraySet;
 import java.util.function.Consumer;
+import java.util.function.Function;
 import java.util.function.Predicate;
 
 /**
@@ -83,7 +84,6 @@ public final class ConnectionManager {
 
     /**
      * Finds the closest player matching a given username.
-     * <p>
      *
      * @param username the player username (can be partial)
      * @return the closest match, null if no players are online
@@ -91,18 +91,17 @@ public final class ConnectionManager {
     public @Nullable Player findPlayer(@NotNull String username) {
         Player exact = getPlayer(username);
         if (exact != null) return exact;
+        final String username1 = username.toLowerCase(Locale.ROOT);
 
-        String lowercase = username.toLowerCase();
+        Function<Player, Double> distanceFunction = player -> {
-        double currentDistance = 0;
+            final String username2 = player.getUsername().toLowerCase(Locale.ROOT);
-        for (Player player : getOnlinePlayers()) {
+            return StringUtils.jaroWinklerScore(username1, username2);
-            final JaroWinklerDistance jaroWinklerDistance = new JaroWinklerDistance();
+        };
-            final double distance = jaroWinklerDistance.apply(lowercase, player.getUsername().toLowerCase());
+        return getOnlinePlayers()
-            if (distance > currentDistance) {
+                .stream()
-                currentDistance = distance;
+                .min(Comparator.comparingDouble(distanceFunction::apply))
-                exact = player;
+                .filter(player -> distanceFunction.apply(player) > 0)
-            }
+                .orElse(null);
-        }
-        return exact;
     }
 
     /**
@@ -188,8 +187,12 @@ public final class ConnectionManager {
      * Gets all the listeners which are called for each packet received.
      *
      * @return a list of packet's consumers
+     * @deprecated all packet listening methods will ultimately be removed.
+     * May or may not work depending on the packet.
+     * It is instead recommended to use a proxy, improving scalability and increasing server performance
      */
     @NotNull
+    @Deprecated
     public List<ClientPacketConsumer> getReceivePacketConsumers() {
         return receiveClientPacketConsumers;
     }
@@ -198,7 +201,11 @@ public final class ConnectionManager {
      * Adds a consumer to call once a packet is received.
      *
      * @param clientPacketConsumer the packet consumer
+     * @deprecated all packet listening methods will ultimately be removed.
+     * May or may not work depending on the packet.
+     * It is instead recommended to use a proxy, improving scalability and increasing server performance
      */
+    @Deprecated
     public void onPacketReceive(@NotNull ClientPacketConsumer clientPacketConsumer) {
         this.receiveClientPacketConsumers.add(clientPacketConsumer);
     }
@@ -207,8 +214,12 @@ public final class ConnectionManager {
      * Gets all the listeners which are called for each packet sent.
      *
      * @return a list of packet's consumers
+     * @deprecated all packet listening methods will ultimately be removed.
+     * May or may not work depending on the packet.
+     * It is instead recommended to use a proxy, improving scalability and increasing server performance
      */
     @NotNull
+    @Deprecated
     public List<ServerPacketConsumer> getSendPacketConsumers() {
         return sendClientPacketConsumers;
     }
@@ -217,7 +228,11 @@ public final class ConnectionManager {
      * Adds a consumer to call once a packet is sent.
      *
      * @param serverPacketConsumer the packet consumer
+     * @deprecated all packet listening methods will ultimately be removed.
+     * May or may not work depending on the packet.
+     * It is instead recommended to use a proxy, improving scalability and increasing server performance
      */
+    @Deprecated
     public void onPacketSend(@NotNull ServerPacketConsumer serverPacketConsumer) {
         this.sendClientPacketConsumers.add(serverPacketConsumer);
     }

src/main/java/net/minestom/server/network/packet/client/login/EncryptionResponsePacket.java

@@ -1,7 +1,7 @@
 package net.minestom.server.network.packet.client.login;
 
-import com.mojang.authlib.GameProfile;
+import com.google.gson.Gson;
-import com.mojang.authlib.exceptions.AuthenticationUnavailableException;
+import com.google.gson.JsonObject;
 import net.minestom.server.MinecraftServer;
 import net.minestom.server.data.type.array.ByteArrayData;
 import net.minestom.server.extras.MojangAuth;
@@ -15,11 +15,16 @@ import net.minestom.server.utils.binary.BinaryWriter;
 import org.jetbrains.annotations.NotNull;
 
 import javax.crypto.SecretKey;
+import java.io.IOException;
+import java.io.InputStream;
+import java.io.InputStreamReader;
 import java.math.BigInteger;
+import java.net.URL;
 import java.util.Arrays;
+import java.util.UUID;
 
 public class EncryptionResponsePacket implements ClientPreplayPacket {
-
+    private static final Gson GSON = new Gson();
     private byte[] sharedSecret;
     private byte[] verifyToken;
 
@@ -44,7 +49,7 @@ public class EncryptionResponsePacket implements ClientPreplayPacket {
                     MinecraftServer.LOGGER.error("{} tried to login with an invalid nonce!", loginUsername);
                     return;
                 }
-                if (!loginUsername.isEmpty()) {
+                if (loginUsername != null && !loginUsername.isEmpty()) {
 
                     final byte[] digestedData = MojangCrypt.digestData("", MojangAuth.getKeyPair().getPublic(), getSecretKey());
 
@@ -55,14 +60,24 @@ public class EncryptionResponsePacket implements ClientPreplayPacket {
                         return;
                     }
 
-                    final String string3 = new BigInteger(digestedData).toString(16);
+                    // Query Mojang's sessionserver.
-                    final GameProfile gameProfile = MojangAuth.getSessionService().hasJoinedServer(new GameProfile(null, loginUsername), string3);
+                    final String serverId = new BigInteger(digestedData).toString(16);
-                    nettyConnection.setEncryptionKey(getSecretKey());
+                    InputStream gameProfileStream = new URL(
+                            "https://sessionserver.mojang.com/session/minecraft/hasJoined?"
+                                    + "username=" + loginUsername + "&"
+                                    + "serverId=" + serverId
+                            // TODO: Add ability to add ip query tag. See: https://wiki.vg/Protocol_Encryption#Authentication
+                    ).openStream();
 
-                    MinecraftServer.LOGGER.info("UUID of player {} is {}", loginUsername, gameProfile.getId());
+                    final JsonObject gameProfile = GSON.fromJson(new InputStreamReader(gameProfileStream), JsonObject.class);
-                    CONNECTION_MANAGER.startPlayState(connection, gameProfile.getId(), gameProfile.getName(), true);
+                    nettyConnection.setEncryptionKey(getSecretKey());
+                    UUID profileUUID = UUID.fromString(gameProfile.get("id").getAsString().replaceFirst("(\\w{8})(\\w{4})(\\w{4})(\\w{4})(\\w{12})", "$1-$2-$3-$4-$5"));
+                    String profileName = gameProfile.get("name").getAsString();
+
+                    MinecraftServer.LOGGER.info("UUID of player {} is {}", loginUsername, profileUUID);
+                    CONNECTION_MANAGER.startPlayState(connection, profileUUID, profileName, true);
                 }
-            } catch (AuthenticationUnavailableException e) {
+            } catch (IOException e) {
                 MinecraftServer.getExceptionManager().handleException(e);
             }
         });
@@ -80,11 +95,11 @@ public class EncryptionResponsePacket implements ClientPreplayPacket {
         ByteArrayData.encodeByteArray(writer, verifyToken);
     }
 
-    public SecretKey getSecretKey() {
+    private SecretKey getSecretKey() {
         return MojangCrypt.decryptByteToSecretKey(MojangAuth.getKeyPair().getPrivate(), sharedSecret);
     }
 
-    public byte[] getNonce() {
+    private byte[] getNonce() {
         return MojangAuth.getKeyPair().getPrivate() == null ?
                 this.verifyToken : MojangCrypt.decryptUsingKey(MojangAuth.getKeyPair().getPrivate(), this.verifyToken);
     }

src/main/java/net/minestom/server/network/packet/client/play/ClientSettingsPacket.java

@@ -1,6 +1,7 @@
 package net.minestom.server.network.packet.client.play;
 
 import net.minestom.server.entity.Player;
+import net.minestom.server.message.ChatMessageType;
 import net.minestom.server.network.packet.client.ClientPlayPacket;
 import net.minestom.server.utils.binary.BinaryReader;
 import net.minestom.server.utils.binary.BinaryWriter;
@@ -10,7 +11,7 @@ public class ClientSettingsPacket extends ClientPlayPacket {
 
     public String locale = "";
     public byte viewDistance;
-    public Player.ChatMode chatMode = Player.ChatMode.ENABLED;
+    public ChatMessageType chatMessageType = ChatMessageType.FULL;
     public boolean chatColors;
     public byte displayedSkinParts;
     public Player.MainHand mainHand = Player.MainHand.RIGHT;
@@ -19,7 +20,7 @@ public class ClientSettingsPacket extends ClientPlayPacket {
     public void read(@NotNull BinaryReader reader) {
         this.locale = reader.readSizedString(128);
         this.viewDistance = reader.readByte();
-        this.chatMode = Player.ChatMode.values()[reader.readVarInt()];
+        this.chatMessageType = ChatMessageType.fromPacketID(reader.readVarInt());
         this.chatColors = reader.readBoolean();
         this.displayedSkinParts = reader.readByte();
         this.mainHand = Player.MainHand.values()[reader.readVarInt()];
@@ -31,7 +32,7 @@ public class ClientSettingsPacket extends ClientPlayPacket {
             throw new IllegalArgumentException("Locale cannot be longer than 128 characters.");
         writer.writeSizedString(locale);
         writer.writeByte(viewDistance);
-        writer.writeVarInt(chatMode.ordinal());
+        writer.writeVarInt(chatMessageType.getPacketID());
         writer.writeBoolean(chatColors);
         writer.writeByte(displayedSkinParts);
         writer.writeVarInt(mainHand.ordinal());

src/main/java/net/minestom/server/network/packet/server/play/ChatMessagePacket.java

@@ -1,7 +1,7 @@
 package net.minestom.server.network.packet.server.play;
 
-import net.kyori.adventure.audience.MessageType;
 import net.kyori.adventure.text.Component;
+import net.minestom.server.message.ChatPosition;
 import net.minestom.server.network.packet.server.ComponentHoldingServerPacket;
 import net.minestom.server.network.packet.server.ServerPacket;
 import net.minestom.server.network.packet.server.ServerPacketIdentifier;
@@ -12,6 +12,7 @@ import org.jetbrains.annotations.Nullable;
 
 import java.util.Collection;
 import java.util.Collections;
+import java.util.Objects;
 import java.util.UUID;
 import java.util.function.UnaryOperator;
 
@@ -22,21 +23,19 @@ public class ChatMessagePacket implements ComponentHoldingServerPacket {
     private static final UUID NULL_UUID = new UUID(0, 0);
 
     public Component message;
-    public Position position;
+    public ChatPosition position;
     public UUID uuid;
 
     public ChatMessagePacket() {
-        this(Component.empty(), Position.CHAT);
+        this.message = Component.empty();
+        this.position = ChatPosition.SYSTEM_MESSAGE;
+        this.uuid = NULL_UUID;
     }
 
-    public ChatMessagePacket(Component message, Position position, UUID uuid) {
+    public ChatMessagePacket(@NotNull Component message, @NotNull ChatPosition position, @Nullable UUID uuid) {
         this.message = message;
         this.position = position;
-        this.uuid = uuid;
+        this.uuid = Objects.requireNonNullElse(uuid, NULL_UUID);
-    }
-
-    public ChatMessagePacket(Component message, Position position) {
-        this(message, position, NULL_UUID);
     }
 
     @Override
@@ -49,7 +48,7 @@ public class ChatMessagePacket implements ComponentHoldingServerPacket {
     @Override
     public void read(@NotNull BinaryReader reader) {
         message = reader.readComponent(Integer.MAX_VALUE);
-        position = Position.values()[reader.readByte()];
+        position = ChatPosition.fromPacketID(reader.readByte());
         uuid = reader.readUuid();
     }
 
@@ -67,41 +66,4 @@ public class ChatMessagePacket implements ComponentHoldingServerPacket {
     public @NotNull ServerPacket copyWithOperator(@NotNull UnaryOperator<Component> operator) {
         return new ChatMessagePacket(operator.apply(message), position, uuid);
     }
-
-    public enum Position {
-        CHAT(MessageType.CHAT),
-        SYSTEM_MESSAGE(MessageType.SYSTEM),
-        GAME_INFO(null);
-
-        private final MessageType messageType;
-
-        Position(MessageType messageType) {
-            this.messageType = messageType;
-        }
-
-        /**
-         * Gets the Adventure message type from this position. Note that there is no
-         * message type for {@link #GAME_INFO}, as Adventure uses the title methods for this.
-         *
-         * @return the message type, if any
-         */
-        public @Nullable MessageType getMessageType() {
-            return this.messageType;
-        }
-
-        /**
-         * Gets a position from an Adventure message type.
-         *
-         * @param messageType the message type
-         *
-         * @return the position
-         */
-        public static @NotNull Position fromMessageType(@NotNull MessageType messageType) {
-            switch (messageType) {
-                case CHAT: return CHAT;
-                case SYSTEM: return SYSTEM_MESSAGE;
-            }
-            throw new IllegalArgumentException("Cannot get position from message type!");
-        }
-    }
 }

src/main/java/net/minestom/server/network/packet/server/play/EntityEquipmentPacket.java

@@ -1,6 +1,6 @@
 package net.minestom.server.network.packet.server.play;
 
-import net.minestom.server.event.item.ArmorEquipEvent;
+import net.minestom.server.entity.EquipmentSlot;
 import net.minestom.server.item.ItemStack;
 import net.minestom.server.network.packet.server.ServerPacket;
 import net.minestom.server.network.packet.server.ServerPacketIdentifier;
@@ -14,7 +14,7 @@ import java.util.List;
 public class EntityEquipmentPacket implements ServerPacket {
 
     public int entityId;
-    public Slot[] slots;
+    public EquipmentSlot[] slots;
     public ItemStack[] itemStacks;
 
     public EntityEquipmentPacket() {
@@ -33,7 +33,7 @@ public class EntityEquipmentPacket implements ServerPacket {
         }
 
         for (int i = 0; i < slots.length; i++) {
-            final Slot slot = slots[i];
+            final EquipmentSlot slot = slots[i];
             final ItemStack itemStack = itemStacks[i];
             final boolean last = i == slots.length - 1;
 
@@ -52,17 +52,17 @@ public class EntityEquipmentPacket implements ServerPacket {
         entityId = reader.readVarInt();
 
         boolean hasRemaining = true;
-        List<Slot> slots = new LinkedList<>();
+        List<EquipmentSlot> slots = new LinkedList<>();
         List<ItemStack> stacks = new LinkedList<>();
         while (hasRemaining) {
             byte slotEnum = reader.readByte();
             hasRemaining = (slotEnum & 0x80) == 0x80;
 
-            slots.add(Slot.values()[slotEnum & 0x7F]);
+            slots.add(EquipmentSlot.values()[slotEnum & 0x7F]);
             stacks.add(reader.readItemStack());
         }
 
-        this.slots = slots.toArray(new Slot[0]);
+        this.slots = slots.toArray(new EquipmentSlot[0]);
         this.itemStacks = stacks.toArray(new ItemStack[0]);
     }
 
@@ -71,29 +71,4 @@ public class EntityEquipmentPacket implements ServerPacket {
         return ServerPacketIdentifier.ENTITY_EQUIPMENT;
     }
 
-    public enum Slot {
-        MAIN_HAND,
-        OFF_HAND,
-        BOOTS,
-        LEGGINGS,
-        CHESTPLATE,
-        HELMET;
-
-        @NotNull
-        public static Slot fromArmorSlot(ArmorEquipEvent.ArmorSlot armorSlot) {
-            switch (armorSlot) {
-                case HELMET:
-                    return HELMET;
-                case CHESTPLATE:
-                    return CHESTPLATE;
-                case LEGGINGS:
-                    return LEGGINGS;
-                case BOOTS:
-                    return BOOTS;
-            }
-            throw new IllegalStateException("Something weird happened");
-        }
-
-    }
-
 }

src/main/java/net/minestom/server/network/packet/server/play/TitlePacket.java

@@ -8,7 +8,7 @@ import net.minestom.server.network.packet.server.ServerPacketIdentifier;
 import net.minestom.server.utils.TickUtils;
 import net.minestom.server.utils.binary.BinaryReader;
 import net.minestom.server.utils.binary.BinaryWriter;
-import org.apache.commons.lang3.Validate;
+import net.minestom.server.utils.validate.Check;
 import org.jetbrains.annotations.NotNull;
 
 import java.util.ArrayList;
@@ -32,13 +32,13 @@ public class TitlePacket implements ComponentHoldingServerPacket {
     /**
      * Constructs a new title packet from an action that can take a component argument.
      *
-     * @param action the action
+     * @param action  the action
      * @param payload the payload
      * @throws IllegalArgumentException if the action is not {@link Action#SET_TITLE},
-     * {@link Action#SET_SUBTITLE} or {@link Action#SET_ACTION_BAR}
+     *                                  {@link Action#SET_SUBTITLE} or {@link Action#SET_ACTION_BAR}
      */
     public TitlePacket(@NotNull Action action, @NotNull Component payload) {
-        Validate.isTrue(action == SET_TITLE || action == SET_SUBTITLE || action == SET_ACTION_BAR, "Invalid action type");
+        Check.argCondition(action != SET_TITLE && action != SET_SUBTITLE && action != SET_ACTION_BAR, "Invalid action type");
         this.action = action;
         this.payload = payload;
     }
@@ -48,7 +48,7 @@ public class TitlePacket implements ComponentHoldingServerPacket {
      *
      * @param action the action
      * @throws IllegalArgumentException if the action is not {@link Action#RESET},
-     * or {@link Action#HIDE}
+     *                                  or {@link Action#HIDE}
      */
     public TitlePacket(@NotNull Action action) {
         this.action = action;
@@ -57,8 +57,8 @@ public class TitlePacket implements ComponentHoldingServerPacket {
     /**
      * Constructs a new title packet for {@link Action#SET_TIMES_AND_DISPLAY}.
      *
-     * @param fadeIn the fade in time
+     * @param fadeIn  the fade in time
-     * @param stay the stay time
+     * @param stay    the stay time
      * @param fadeOut the fade out time
      */
     public TitlePacket(int fadeIn, int stay, int fadeOut) {

src/main/java/net/minestom/server/network/player/PlayerConnection.java

@@ -95,7 +95,7 @@ public abstract class PlayerConnection {
     }
 
     /**
-     * Serializes the packet and send it to the client, skipping the translation phase.
+     * Serializes the packet and send it to the client, optionally skipping the translation phase.
      * <p>
      * Also responsible for executing {@link ConnectionManager#onPacketSend(ServerPacketConsumer)} consumers.
      *

src/main/java/net/minestom/server/registry/ResourceGatherer.java

@@ -5,16 +5,27 @@ import com.google.gson.JsonArray;
 import com.google.gson.JsonElement;
 import com.google.gson.JsonObject;
 import it.unimi.dsi.fastutil.io.FastBufferedInputStream;
-import org.apache.commons.codec.digest.DigestUtils;
+import net.minestom.server.utils.StringUtils;
-import org.apache.commons.lang3.StringUtils;
 import org.jetbrains.annotations.NotNull;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 
-import java.io.*;
+import java.io.BufferedReader;
+import java.io.File;
+import java.io.FileInputStream;
+import java.io.IOException;
+import java.io.InputStream;
+import java.io.InputStreamReader;
+import java.math.BigInteger;
 import java.net.URL;
-import java.nio.file.*;
+import java.nio.file.FileVisitResult;
+import java.nio.file.Files;
+import java.nio.file.Path;
+import java.nio.file.SimpleFileVisitor;
+import java.nio.file.StandardCopyOption;
 import java.nio.file.attribute.BasicFileAttributes;
+import java.security.MessageDigest;
+import java.security.NoSuchAlgorithmException;
 
 /**
  * Responsible for making sure Minestom has the necessary files to run (notably registry files)
@@ -177,13 +188,19 @@ public class ResourceGatherer {
         }
         // Verify checksum
         try (FileInputStream fis = new FileInputStream(target)) {
-            String sha1Target = DigestUtils.sha1Hex(fis);
+            MessageDigest messageDigest = MessageDigest.getInstance("SHA-1");
+            messageDigest.reset();
+            // This just converts the sha1 back into a readable string.
+            String sha1Target = new BigInteger(1, messageDigest.digest(fis.readAllBytes())).toString(16);
             if (!sha1Target.equals(sha1Source)) {
-                LOGGER.debug("The checksum test failed after downloading the Minecraft server jar.");
+                LOGGER.error("The checksum test failed after downloading the Minecraft server jar.");
-                LOGGER.debug("The expected checksum was: {}.", sha1Source);
+                LOGGER.error("The expected checksum was: {}.", sha1Source);
-                LOGGER.debug("The calculated checksum was: {}.", sha1Target);
+                LOGGER.error("The calculated checksum was: {}.", sha1Target);
                 throw new IOException("Failed to download Minecraft server jar.");
             }
+        } catch (NoSuchAlgorithmException e) {
+            LOGGER.error("Failed to find SHA-1 hashing algorithm in Java Environment.");
+            throw new IOException("Failed to download Minecraft server jar.");
         }
         return target;
     }

src/main/java/net/minestom/server/tag/Tag.java

@@ -0,0 +1,197 @@
+package net.minestom.server.tag;
+
+import org.jetbrains.annotations.ApiStatus;
+import org.jetbrains.annotations.Contract;
+import org.jetbrains.annotations.NotNull;
+import org.jetbrains.annotations.Nullable;
+import org.jglrxavpok.hephaistos.nbt.NBT;
+import org.jglrxavpok.hephaistos.nbt.NBTCompound;
+
+import java.util.function.BiConsumer;
+import java.util.function.Function;
+import java.util.function.Supplier;
+
+/**
+ * Represents a key to retrieve or change a value.
+ * <p>
+ * All tags are serializable.
+ *
+ * @param <T> the tag type
+ */
+@ApiStatus.NonExtendable
+public class Tag<T> {
+
+    private final String key;
+    private final Function<NBTCompound, T> readFunction;
+    private final BiConsumer<NBTCompound, T> writeConsumer;
+
+    private final Supplier<T> defaultValue;
+
+    protected Tag(@NotNull String key,
+                  @NotNull Function<NBTCompound, T> readFunction,
+                  @NotNull BiConsumer<NBTCompound, T> writeConsumer,
+                  @Nullable Supplier<T> defaultValue) {
+        this.key = key;
+        this.readFunction = readFunction;
+        this.writeConsumer = writeConsumer;
+        this.defaultValue = defaultValue;
+    }
+
+    protected Tag(@NotNull String key,
+                  @NotNull Function<NBTCompound, T> readFunction,
+                  @NotNull BiConsumer<NBTCompound, T> writeConsumer) {
+        this(key, readFunction, writeConsumer, null);
+    }
+
+    public @NotNull String getKey() {
+        return key;
+    }
+
+    @Contract(value = "_ -> new", pure = true)
+    public Tag<T> defaultValue(@NotNull Supplier<T> defaultValue) {
+        return new Tag<>(key, readFunction, writeConsumer, defaultValue);
+    }
+
+    @Contract(value = "_ -> new", pure = true)
+    public Tag<T> defaultValue(@NotNull T defaultValue) {
+        return defaultValue(() -> defaultValue);
+    }
+
+    @Contract(value = "_, _ -> new", pure = true)
+    public <R> Tag<R> map(@NotNull Function<T, R> readMap,
+                          @NotNull Function<R, T> writeMap) {
+        return new Tag<R>(key,
+                // Read
+                nbtCompound -> {
+                    final var old = readFunction.apply(nbtCompound);
+                    if (old == null) {
+                        return null;
+                    }
+                    return readMap.apply(old);
+                },
+                // Write
+                (nbtCompound, r) -> {
+                    var n = writeMap.apply(r);
+                    writeConsumer.accept(nbtCompound, n);
+                },
+                // Default value
+                () -> {
+                    if (defaultValue == null) {
+                        return null;
+                    }
+                    var old = defaultValue.get();
+                    return readMap.apply(old);
+                });
+    }
+
+    public @Nullable T read(@NotNull NBTCompound nbtCompound) {
+        if (nbtCompound.containsKey(key)) {
+            return readFunction.apply(nbtCompound);
+        } else {
+            final var supplier = defaultValue;
+            return supplier != null ? supplier.get() : null;
+        }
+    }
+
+    public void write(@NotNull NBTCompound nbtCompound, @Nullable T value) {
+        if (value != null) {
+            this.writeConsumer.accept(nbtCompound, value);
+        } else {
+            nbtCompound.removeTag(key);
+        }
+    }
+
+    public static @NotNull Tag<Byte> Byte(@NotNull String key) {
+        return new Tag<>(key,
+                nbtCompound -> nbtCompound.getByte(key),
+                (nbtCompound, value) -> nbtCompound.setByte(key, value));
+    }
+
+    public static @NotNull Tag<Short> Short(@NotNull String key) {
+        return new Tag<>(key,
+                nbtCompound -> nbtCompound.getShort(key),
+                (nbtCompound, value) -> nbtCompound.setShort(key, value));
+    }
+
+    public static @NotNull Tag<Integer> Integer(@NotNull String key) {
+        return new Tag<>(key,
+                nbtCompound -> nbtCompound.getInt(key),
+                (nbtCompound, integer) -> nbtCompound.setInt(key, integer));
+    }
+
+    public static @NotNull Tag<Long> Long(@NotNull String key) {
+        return new Tag<>(key,
+                nbtCompound -> nbtCompound.getLong(key),
+                (nbtCompound, value) -> nbtCompound.setLong(key, value));
+    }
+
+    public static @NotNull Tag<Float> Float(@NotNull String key) {
+        return new Tag<>(key,
+                nbtCompound -> nbtCompound.getFloat(key),
+                (nbtCompound, value) -> nbtCompound.setFloat(key, value));
+    }
+
+    public static @NotNull Tag<Double> Double(@NotNull String key) {
+        return new Tag<>(key,
+                nbtCompound -> nbtCompound.getDouble(key),
+                (nbtCompound, value) -> nbtCompound.setDouble(key, value));
+    }
+
+    public static @NotNull Tag<byte[]> ByteArray(@NotNull String key) {
+        return new Tag<>(key,
+                nbtCompound -> nbtCompound.getByteArray(key),
+                (nbtCompound, value) -> nbtCompound.setByteArray(key, value));
+    }
+
+    public static @NotNull Tag<String> String(@NotNull String key) {
+        return new Tag<>(key,
+                nbtCompound -> nbtCompound.getString(key),
+                (nbtCompound, value) -> nbtCompound.setString(key, value));
+    }
+
+    public static @NotNull Tag<NBT> NBT(@NotNull String key) {
+        return new Tag<>(key,
+                nbt -> {
+                    var currentNBT = nbt.get(key);
+
+                    // Avoid a NPE when cloning a null variable.
+                    if (currentNBT == null) {
+                        return null;
+                    }
+
+                    return currentNBT.deepClone();
+                },
+                ((nbt, value) -> nbt.set(key, value.deepClone())));
+    }
+
+    public static @NotNull Tag<int[]> IntArray(@NotNull String key) {
+        return new Tag<>(key,
+                nbtCompound -> nbtCompound.getIntArray(key),
+                (nbtCompound, value) -> nbtCompound.setIntArray(key, value));
+    }
+
+    public static @NotNull Tag<long[]> LongArray(@NotNull String key) {
+        return new Tag<>(key,
+                nbtCompound -> nbtCompound.getLongArray(key),
+                (nbtCompound, value) -> nbtCompound.setLongArray(key, value));
+    }
+
+    public static <T> @NotNull Tag<T> Custom(@NotNull String key, @NotNull TagSerializer<T> serializer) {
+        return new Tag<>(key,
+                nbtCompound -> {
+                    final var compound = nbtCompound.getCompound(key);
+                    if (compound == null) {
+                        return null;
+                    }
+                    return serializer.read(TagReadable.fromCompound(compound));
+                },
+                (nbtCompound, value) -> {
+                    var compound = nbtCompound.getCompound(key);
+                    if (compound == null) {
+                        compound = new NBTCompound();
+                        nbtCompound.set(key, compound);
+                    }
+                    serializer.write(TagWritable.fromCompound(compound), value);
+                });
+    }
+}

src/main/java/net/minestom/server/tag/TagHandler.java

@@ -0,0 +1,10 @@
+package net.minestom.server.tag;
+
+import com.google.common.annotations.Beta;
+
+/**
+ * Represents an element which can read and write {@link Tag tags}.
+ */
+@Beta
+public interface TagHandler extends TagReadable, TagWritable {
+}

src/main/java/net/minestom/server/tag/TagReadable.java

@@ -0,0 +1,48 @@
+package net.minestom.server.tag;
+
+import org.jetbrains.annotations.NotNull;
+import org.jetbrains.annotations.Nullable;
+import org.jglrxavpok.hephaistos.nbt.NBTCompound;
+
+/**
+ * Represents an element which can read {@link Tag tags}.
+ */
+public interface TagReadable {
+
+    /**
+     * Reads the specified tag.
+     *
+     * @param tag the tag to read
+     * @param <T> the tag type
+     * @return the read tag, null if not present
+     */
+    <T> @Nullable T getTag(@NotNull Tag<T> tag);
+
+    /**
+     * Returns if a tag is present.
+     *
+     * @param tag the tag to check
+     * @return true if the tag is present, false otherwise
+     */
+    boolean hasTag(@NotNull Tag<?> tag);
+
+    /**
+     * Converts an nbt compound to a tag reader.
+     *
+     * @param compound the compound to convert
+     * @return a {@link TagReadable} capable of reading {@code compound}
+     */
+    static @NotNull TagReadable fromCompound(@NotNull NBTCompound compound) {
+        return new TagReadable() {
+            @Override
+            public <T> @Nullable T getTag(@NotNull Tag<T> tag) {
+                return tag.read(compound);
+            }
+
+            @Override
+            public boolean hasTag(@NotNull Tag<?> tag) {
+                return compound.containsKey(tag.getKey());
+            }
+        };
+    }
+}

src/main/java/net/minestom/server/tag/TagSerializer.java

@@ -0,0 +1,28 @@
+package net.minestom.server.tag;
+
+import org.jetbrains.annotations.NotNull;
+import org.jetbrains.annotations.Nullable;
+
+/**
+ * Interface used to create custom types compatible with {@link Tag#Custom(String, TagSerializer)}.
+ *
+ * @param <T> the type to serialize
+ */
+public interface TagSerializer<T> {
+
+    /**
+     * Reads the custom tag from a {@link TagReadable}.
+     *
+     * @param reader the reader
+     * @return the deserialized value
+     */
+    @Nullable T read(@NotNull TagReadable reader);
+
+    /**
+     * Writes the custom tag to a {@link TagWritable}.
+     *
+     * @param writer the writer
+     * @param value  the value to serialize
+     */
+    void write(@NotNull TagWritable writer, @NotNull T value);
+}

src/main/java/net/minestom/server/tag/TagWritable.java

@@ -0,0 +1,35 @@
+package net.minestom.server.tag;
+
+import org.jetbrains.annotations.NotNull;
+import org.jetbrains.annotations.Nullable;
+import org.jglrxavpok.hephaistos.nbt.NBTCompound;
+
+/**
+ * Represents an element which can write {@link Tag tags}.
+ */
+public interface TagWritable {
+
+    /**
+     * Writes the specified type.
+     *
+     * @param tag   the tag to write
+     * @param value the tag value, null to remove
+     * @param <T>   the tag type
+     */
+    <T> void setTag(@NotNull Tag<T> tag, @Nullable T value);
+
+    /**
+     * Converts an nbt compound to a tag writer.
+     *
+     * @param compound the compound to convert
+     * @return a {@link TagWritable} capable of writing {@code compound}
+     */
+    static @NotNull TagWritable fromCompound(@NotNull NBTCompound compound) {
+        return new TagWritable() {
+            @Override
+            public <T> void setTag(@NotNull Tag<T> tag, @Nullable T value) {
+                tag.write(compound, value);
+            }
+        };
+    }
+}

src/main/java/net/minestom/server/utils/StringUtils.java

@@ -0,0 +1,161 @@
+package net.minestom.server.utils;
+
+import org.jetbrains.annotations.NotNull;
+
+public class StringUtils {
+
+    public static final String SPACE = " ";
+    public static final char SPACE_CHAR = ' ';
+
+    public static int countMatches(@NotNull final CharSequence str, final char ch) {
+        if (str.length() == 0) {
+            return 0;
+        }
+        int count = 0;
+        // We could also call str.toCharArray() for faster look ups but that would generate more garbage.
+        for (int i = 0; i < str.length(); i++) {
+            if (ch == str.charAt(i)) {
+                count++;
+            }
+        }
+        return count;
+    }
+
+    /**
+     * Applies the Jaro-Winkler distance algorithm to the given strings, providing information about the
+     * similarity of them.
+     *
+     * @param s1 The first string that gets compared. May be null or empty.
+     * @param s2 The second string that gets compared. May be null or empty.
+     * @return The Jaro-Winkler score (between 0.0 and 1.0), with a higher value indicating larger similarity.
+     * @author Thomas Trojer thomas@trojer.net
+     */
+    public static double jaroWinklerScore(final String s1, final String s2) {
+        // lowest score on empty strings
+        if (s1 == null || s2 == null || s1.isEmpty() || s2.isEmpty()) {
+            return 0;
+        }
+        // highest score on equal strings
+        if (s1.equals(s2)) {
+            return 1;
+        }
+        // some score on different strings
+        int prefixMatch = 0; // exact prefix matches
+        int matches = 0; // matches (including prefix and ones requiring transpostion)
+        int transpositions = 0; // matching characters that are not aligned but close together
+        int maxLength = Math.max(s1.length(), s2.length());
+        int maxMatchDistance = Math.max((int) Math.floor(maxLength / 2.0) - 1, 0); // look-ahead/-behind to limit transposed matches
+        // comparison
+        final String shorter = s1.length() < s2.length() ? s1 : s2;
+        final String longer = s1.length() >= s2.length() ? s1 : s2;
+        for (int i = 0; i < shorter.length(); i++) {
+            // check for exact matches
+            boolean match = shorter.charAt(i) == longer.charAt(i);
+            if (match) {
+                if (i < 4) {
+                    // prefix match (of at most 4 characters, as described by the algorithm)
+                    prefixMatch++;
+                }
+                matches++;
+                continue;
+            }
+            // check fro transposed matches
+            for (int j = Math.max(i - maxMatchDistance, 0); j < Math.min(i + maxMatchDistance, longer.length()); j++) {
+                if (i == j) {
+                    // case already covered
+                    continue;
+                }
+                // transposition required to match?
+                match = shorter.charAt(i) == longer.charAt(j);
+                if (match) {
+                    transpositions++;
+                    break;
+                }
+            }
+        }
+        // any matching characters?
+        if (matches == 0) {
+            return 0;
+        }
+        // modify transpositions (according to the algorithm)
+        transpositions = (int) (transpositions / 2.0);
+        // non prefix-boosted score
+        double score = 0.3334 * (matches / (double) longer.length() + matches / (double) shorter.length() + (matches - transpositions)
+                / (double) matches);
+        if (score < 0.7) {
+            return score;
+        }
+        // we already have a good match, hence we boost the score proportional to the common prefix
+        return score + prefixMatch * 0.1 * (1.0 - score);
+    }
+
+    public static String unescapeJavaString(String st) {
+        StringBuilder sb = new StringBuilder(st.length());
+
+        for (int i = 0; i < st.length(); i++) {
+            char ch = st.charAt(i);
+            if (ch == '\\') {
+                char nextChar = (i == st.length() - 1) ? '\\' : st
+                        .charAt(i + 1);
+                // Octal escape?
+                if (nextChar >= '0' && nextChar <= '7') {
+                    String code = "" + nextChar;
+                    i++;
+                    if ((i < st.length() - 1) && st.charAt(i + 1) >= '0'
+                            && st.charAt(i + 1) <= '7') {
+                        code += st.charAt(i + 1);
+                        i++;
+                        if ((i < st.length() - 1) && st.charAt(i + 1) >= '0'
+                                && st.charAt(i + 1) <= '7') {
+                            code += st.charAt(i + 1);
+                            i++;
+                        }
+                    }
+                    sb.append((char) Integer.parseInt(code, 8));
+                    continue;
+                }
+                switch (nextChar) {
+                    case '\\':
+                        ch = '\\';
+                        break;
+                    case 'b':
+                        ch = '\b';
+                        break;
+                    case 'f':
+                        ch = '\f';
+                        break;
+                    case 'n':
+                        ch = '\n';
+                        break;
+                    case 'r':
+                        ch = '\r';
+                        break;
+                    case 't':
+                        ch = '\t';
+                        break;
+                    case '\"':
+                        ch = '\"';
+                        break;
+                    case '\'':
+                        ch = '\'';
+                        break;
+                    // Hex Unicode: u????
+                    case 'u':
+                        if (i >= st.length() - 5) {
+                            ch = 'u';
+                            break;
+                        }
+                        int code = Integer.parseInt(
+                                "" + st.charAt(i + 2) + st.charAt(i + 3)
+                                        + st.charAt(i + 4) + st.charAt(i + 5), 16);
+                        sb.append(Character.toChars(code));
+                        i += 5;
+                        continue;
+                }
+                i++;
+            }
+            sb.append(ch);
+        }
+        return sb.toString();
+    }
+}

src/main/java/net/minestom/server/utils/TickUtils.java

@@ -1,7 +1,7 @@
 package net.minestom.server.utils;
 
 import net.minestom.server.MinecraftServer;
-import org.apache.commons.lang3.Validate;
+import net.minestom.server.utils.validate.Check;
 import org.jetbrains.annotations.NotNull;
 
 import java.time.Duration;
@@ -22,6 +22,7 @@ public class TickUtils {
 
     /**
      * Creates a number of ticks from a given duration, based on {@link MinecraftServer#TICK_MS}.
+     *
      * @param duration the duration
      * @return the number of ticks
      * @throws IllegalArgumentException if duration is negative
@@ -32,14 +33,14 @@ public class TickUtils {
 
     /**
      * Creates a number of ticks from a given duration.
-     * @param duration the duration
+     *
+     * @param duration  the duration
      * @param msPerTick the number of milliseconds per tick
      * @return the number of ticks
      * @throws IllegalArgumentException if duration is negative
      */
     public static int fromDuration(@NotNull Duration duration, int msPerTick) {
-        Validate.isTrue(!duration.isNegative(), "Duration cannot be negative");
+        Check.argCondition(duration.isNegative(), "Duration cannot be negative");
-
         return (int) (duration.toMillis() / msPerTick);
     }
 }

src/main/java/net/minestom/server/utils/Utils.java

@@ -118,16 +118,11 @@ public final class Utils {
     }
 
     public static void writeSectionBlocks(ByteBuf buffer, Section section) {
-        /*short count = 0;
-        for (short id : blocksId)
-            if (id != 0)
-                count++;*/
 
+        final short blockCount = section.getBlockCount();
         final int bitsPerEntry = section.getBitsPerEntry();
 
-        //buffer.writeShort(count);
+        buffer.writeShort(blockCount);
-        // TODO count blocks
-        buffer.writeShort(200);
         buffer.writeByte((byte) bitsPerEntry);
 
         // Palette

src/main/java/net/minestom/server/utils/cache/TemporaryCache.java

@@ -26,7 +26,6 @@ public class TemporaryCache<T> {
     public TemporaryCache(long duration, TimeUnit timeUnit, RemovalListener<UUID, T> removalListener) {
         this.cache = CacheBuilder.newBuilder()
                 .expireAfterWrite(duration, timeUnit)
-                .softValues()
                 .removalListener(removalListener)
                 .build();
     }

src/main/java/net/minestom/server/utils/mojang/MojangUtils.java

@@ -27,7 +27,6 @@ public final class MojangUtils {
             .softValues()
             .build();
 
-
     @Nullable
     public static JsonObject fromUuid(@NotNull String uuid) {
 

src/test/java/demo/commands/EchoCommand.java

@@ -1,24 +1,32 @@
 package demo.commands;
 
+import net.kyori.adventure.audience.MessageType;
+import net.kyori.adventure.identity.Identity;
 import net.kyori.adventure.text.Component;
 import net.kyori.adventure.text.event.ClickEvent;
 import net.minestom.server.command.builder.Command;
 import net.minestom.server.command.builder.arguments.ArgumentType;
 import net.minestom.server.command.builder.arguments.minecraft.ArgumentComponent;
+import net.minestom.server.command.builder.arguments.minecraft.ArgumentUUID;
 
 public class EchoCommand extends Command {
     public EchoCommand() {
         super("echo");
 
         this.setDefaultExecutor((sender, context) -> sender.sendMessage(
-                Component.text("Usage: /echo <json>")
+                Component.text("Usage: /echo <json> [uuid]")
                         .hoverEvent(Component.text("Click to get this command.")
                         .clickEvent(ClickEvent.suggestCommand("/echo ")))));
 
         ArgumentComponent json = ArgumentType.Component("json");
+        ArgumentUUID uuid = ArgumentType.UUID("uuid");
 
         this.addSyntax((sender, context) -> {
             sender.sendMessage(context.get(json));
         }, json);
+
+        this.addSyntax((sender, context) -> {
+            sender.sendMessage(Identity.identity(context.get(uuid)), context.get(json), MessageType.CHAT);
+        }, uuid, json);
     }
 }

src/test/java/readwritepackets/ReadWritePackets.java

@@ -2,6 +2,7 @@ package readwritepackets;
 
 import com.google.common.reflect.ClassPath;
 import net.minestom.server.MinecraftServer;
+import net.minestom.server.entity.EquipmentSlot;
 import net.minestom.server.item.ItemStack;
 import net.minestom.server.network.packet.client.ClientPacket;
 import net.minestom.server.network.packet.server.ServerPacket;
@@ -67,7 +68,7 @@ public class ReadWritePackets {
                             // requires at least one slot and one item
                             EntityEquipmentPacket p = new EntityEquipmentPacket();
                             p.itemStacks = new ItemStack[]{ItemStack.AIR};
-                            p.slots = new EntityEquipmentPacket.Slot[]{EntityEquipmentPacket.Slot.MAIN_HAND};
+                            p.slots = new EquipmentSlot[]{EquipmentSlot.MAIN_HAND};
                             packet = (T) p;
                         } else {
                             packet = (T) constructor.newInstance();