Merge branch 'master' into new-position-api

build.gradle

@@ -36,9 +36,6 @@ allprojects {
             name 'sponge'
             url 'https://repo.spongepowered.org/maven'
         }
-        maven {
-            url "https://repo.velocitypowered.com/snapshots/"
-        }
     }
     javadoc {
         options {
@@ -111,11 +108,10 @@ dependencies {
     testCompileOnly "org.mockito:mockito-core:2.28.2"
 
     // Netty
-    api 'io.netty:netty-handler:4.1.63.Final'
+    api 'io.netty:netty-handler:4.1.65.Final'
-    api 'io.netty:netty-codec:4.1.63.Final'
+    api 'io.netty:netty-codec:4.1.65.Final'
-    api 'io.netty:netty-transport-native-epoll:4.1.63.Final:linux-x86_64'
+    api 'io.netty:netty-transport-native-epoll:4.1.65.Final:linux-x86_64'
-    api 'io.netty:netty-transport-native-kqueue:4.1.63.Final:osx-x86_64'
+    api 'io.netty:netty-transport-native-kqueue:4.1.65.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/it.unimi.dsi/fastutil
     api 'it.unimi.dsi:fastutil:8.5.4'
@@ -142,6 +138,8 @@ dependencies {
     // https://search.maven.org/artifact/org.fusesource.jansi/jansi/2.3.2/jar
     implementation 'org.fusesource.jansi:jansi:2.3.2'
 
+    implementation 'com.github.ben-manes.caffeine:caffeine:3.0.2'
+
     // Guava 21.0+ required for Mixin
     api 'com.google.guava:guava:30.1-jre'
 
@@ -153,9 +151,6 @@ dependencies {
     api "org.ow2.asm:asm-commons:${asmVersion}"
     api "org.spongepowered:mixin:${mixinVersion}"
 
-    // Compression
-    implementation "com.velocitypowered:velocity-native:1.1.0-SNAPSHOT"
-
     // Path finding
     api 'com.github.MadMartian:hydrazine-path-finding:1.6.0'
 

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

@@ -1,6 +1,5 @@
 package net.minestom.server;
 
-import com.google.common.collect.Queues;
 import net.minestom.server.acquirable.Acquirable;
 import net.minestom.server.instance.Chunk;
 import net.minestom.server.instance.Instance;
@@ -34,8 +33,8 @@ public final class UpdateManager {
     // TODO make configurable
     private ThreadProvider threadProvider = new SingleThreadProvider();
 
-    private final Queue<LongConsumer> tickStartCallbacks = Queues.newConcurrentLinkedQueue();
+    private final Queue<LongConsumer> tickStartCallbacks = new ConcurrentLinkedQueue<>();
-    private final Queue<LongConsumer> tickEndCallbacks = Queues.newConcurrentLinkedQueue();
+    private final Queue<LongConsumer> tickEndCallbacks = new ConcurrentLinkedQueue<>();
     private final List<Consumer<TickMonitor>> tickMonitors = new CopyOnWriteArrayList<>();
 
     /**

src/main/java/net/minestom/server/acquirable/Acquirable.java

@@ -1,6 +1,5 @@
 package net.minestom.server.acquirable;
 
-import com.google.common.annotations.Beta;
 import net.minestom.server.entity.Entity;
 import net.minestom.server.thread.ThreadProvider;
 import net.minestom.server.thread.TickThread;
@@ -14,7 +13,7 @@ import java.util.Optional;
 import java.util.function.Consumer;
 import java.util.stream.Stream;
 
-@Beta
+@ApiStatus.Experimental
 public interface Acquirable<T> {
 
     /**

src/main/java/net/minestom/server/acquirable/AcquirableCollection.java

@@ -1,15 +1,15 @@
 package net.minestom.server.acquirable;
 
-import com.google.common.annotations.Beta;
 import net.minestom.server.thread.TickThread;
 import net.minestom.server.utils.async.AsyncUtils;
+import org.jetbrains.annotations.ApiStatus;
 import org.jetbrains.annotations.NotNull;
 
 import java.util.*;
 import java.util.function.Consumer;
 import java.util.stream.Stream;
 
-@Beta
+@ApiStatus.Experimental
 public class AcquirableCollection<E> implements Collection<Acquirable<E>> {
 
     private final Collection<Acquirable<E>> acquirableCollection;

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

@@ -14,6 +14,7 @@ import net.minestom.server.adventure.AdventurePacketConvertor;
 import net.minestom.server.entity.Player;
 import net.minestom.server.message.ChatPosition;
 import net.minestom.server.message.Messenger;
+import net.minestom.server.network.packet.server.ServerPacket;
 import net.minestom.server.network.packet.server.play.*;
 import net.minestom.server.utils.PacketUtils;
 import org.jetbrains.annotations.NotNull;
@@ -44,6 +45,14 @@ public interface PacketGroupingAudience extends ForwardingAudience {
      */
     @NotNull Collection<Player> getPlayers();
 
+    /**
+     * Broadcast a ServerPacket to all players of this audience
+     * @param packet the packet to broadcast
+     */
+    default void sendGroupedPacket(ServerPacket packet) {
+        PacketUtils.sendGroupedPacket(this.getPlayers(), packet);
+    }
+
     @Override
     default void sendMessage(@NotNull Identity source, @NotNull Component message, @NotNull MessageType type) {
         Messenger.sendMessage(this.getPlayers(), message, ChatPosition.fromMessageType(type), source.uuid());
@@ -51,28 +60,28 @@ public interface PacketGroupingAudience extends ForwardingAudience {
 
     @Override
     default void sendActionBar(@NotNull Component message) {
-        PacketUtils.sendGroupedPacket(this.getPlayers(), new ActionBarPacket(message));
+        sendGroupedPacket(new ActionBarPacket(message));
     }
 
     @Override
     default void sendPlayerListHeaderAndFooter(@NotNull Component header, @NotNull Component footer) {
-        PacketUtils.sendGroupedPacket(this.getPlayers(), new PlayerListHeaderAndFooterPacket(header, footer));
+        sendGroupedPacket(new PlayerListHeaderAndFooterPacket(header, footer));
     }
 
     @Override
     default void showTitle(@NotNull Title title) {
-        PacketUtils.sendGroupedPacket(this.getPlayers(), new SetTitleTextPacket(title.title()));
+        sendGroupedPacket(new SetTitleTextPacket(title.title()));
-        PacketUtils.sendGroupedPacket(this.getPlayers(), new SetTitleSubTitlePacket(title.subtitle()));
+        sendGroupedPacket(new SetTitleSubTitlePacket(title.subtitle()));
     }
 
     @Override
     default void clearTitle() {
-        PacketUtils.sendGroupedPacket(this.getPlayers(), new ClearTitlesPacket());
+        sendGroupedPacket(new ClearTitlesPacket());
     }
 
     @Override
     default void resetTitle() {
-        PacketUtils.sendGroupedPacket(this.getPlayers(), new ClearTitlesPacket(true));
+        sendGroupedPacket(new ClearTitlesPacket(true));
     }
 
     @Override
@@ -87,13 +96,13 @@ public interface PacketGroupingAudience extends ForwardingAudience {
 
     @Override
     default void playSound(@NotNull Sound sound, double x, double y, double z) {
-        PacketUtils.sendGroupedPacket(this.getPlayers(), AdventurePacketConvertor.createSoundPacket(sound, x, y, z));
+        sendGroupedPacket(AdventurePacketConvertor.createSoundPacket(sound, x, y, z));
     }
 
     @Override
     default void playSound(@NotNull Sound sound, Sound.@NotNull Emitter emitter) {
         if (emitter != Sound.Emitter.self()) {
-            PacketUtils.sendGroupedPacket(this.getPlayers(), AdventurePacketConvertor.createSoundPacket(sound, emitter));
+            sendGroupedPacket(AdventurePacketConvertor.createSoundPacket(sound, emitter));
         } else {
             // if we're playing on self, we need to delegate to each audience member
             for (Audience audience : this.audiences()) {
@@ -104,7 +113,7 @@ public interface PacketGroupingAudience extends ForwardingAudience {
 
     @Override
     default void stopSound(@NotNull SoundStop stop) {
-        PacketUtils.sendGroupedPacket(this.getPlayers(), AdventurePacketConvertor.createSoundStopPacket(stop));
+        sendGroupedPacket(AdventurePacketConvertor.createSoundStopPacket(stop));
     }
 
 

src/main/java/net/minestom/server/attribute/AttributeModifier.java

@@ -1,10 +1,10 @@
 package net.minestom.server.attribute;
 
-import io.netty.util.internal.ThreadLocalRandom;
 import net.minestom.server.utils.UniqueIdUtils;
 import org.jetbrains.annotations.NotNull;
 
 import java.util.UUID;
+import java.util.concurrent.ThreadLocalRandom;
 
 /**
  * Represent an attribute modifier.

src/main/java/net/minestom/server/command/CommandSender.java

@@ -5,6 +5,7 @@ import net.kyori.adventure.text.Component;
 import net.minestom.server.chat.JsonMessage;
 import net.minestom.server.entity.Player;
 import net.minestom.server.permission.PermissionHandler;
+import net.minestom.server.tag.TagHandler;
 import org.jetbrains.annotations.NotNull;
 
 /**
@@ -12,7 +13,7 @@ import org.jetbrains.annotations.NotNull;
  * <p>
  * Main implementations are {@link Player} and {@link ConsoleSender}.
  */
-public interface CommandSender extends PermissionHandler, Audience {
+public interface CommandSender extends PermissionHandler, Audience, TagHandler {
 
     /**
      * Sends a raw string message.
@@ -28,7 +29,7 @@ public interface CommandSender extends PermissionHandler, Audience {
      *
      * @param messages the messages to send
      */
-    default void sendMessage(@NotNull String @NotNull[] messages) {
+    default void sendMessage(@NotNull String @NotNull [] messages) {
         for (String message : messages) {
             sendMessage(message);
         }
@@ -39,9 +40,8 @@ public interface CommandSender extends PermissionHandler, Audience {
      * If this is not a {@link Player}, only the content of the message will be sent as a string.
      *
      * @param text The {@link JsonMessage} to send.
-     *
      * @deprecated Use {@link #sendMessage(Component)}
-     * */
+     */
     @Deprecated
     default void sendMessage(@NotNull JsonMessage text) {
         this.sendMessage(text.asComponent());

src/main/java/net/minestom/server/command/ConsoleSender.java

@@ -3,9 +3,12 @@ package net.minestom.server.command;
 import net.kyori.adventure.audience.MessageType;
 import net.kyori.adventure.identity.Identity;
 import net.kyori.adventure.text.Component;
-import net.kyori.adventure.text.serializer.plain.PlainComponentSerializer;
+import net.kyori.adventure.text.serializer.plain.PlainTextComponentSerializer;
 import net.minestom.server.permission.Permission;
+import net.minestom.server.tag.Tag;
 import org.jetbrains.annotations.NotNull;
+import org.jetbrains.annotations.Nullable;
+import org.jglrxavpok.hephaistos.nbt.NBTCompound;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 
@@ -16,10 +19,11 @@ import java.util.concurrent.CopyOnWriteArraySet;
  * Represents the console when sending a command to the server.
  */
 public class ConsoleSender implements CommandSender {
-    private static final PlainComponentSerializer PLAIN_SERIALIZER = PlainComponentSerializer.plain();
+    private static final PlainTextComponentSerializer PLAIN_SERIALIZER = PlainTextComponentSerializer.plainText();
     private static final Logger LOGGER = LoggerFactory.getLogger(ConsoleSender.class);
 
     private final Set<Permission> permissions = new CopyOnWriteArraySet<>();
+    private final NBTCompound nbtCompound = new NBTCompound();
 
     @Override
     public void sendMessage(@NotNull String message) {
@@ -47,4 +51,14 @@ public class ConsoleSender implements CommandSender {
     public ConsoleSender asConsole() {
         return this;
     }
+
+    @Override
+    public <T> @Nullable T getTag(@NotNull Tag<T> tag) {
+        return tag.read(nbtCompound);
+    }
+
+    @Override
+    public <T> void setTag(@NotNull Tag<T> tag, @Nullable T value) {
+        tag.write(nbtCompound, value);
+    }
 }

src/main/java/net/minestom/server/command/ServerSender.java

@@ -3,7 +3,10 @@ package net.minestom.server.command;
 import net.minestom.server.command.builder.CommandContext;
 import net.kyori.adventure.audience.Audience;
 import net.minestom.server.permission.Permission;
+import net.minestom.server.tag.Tag;
 import org.jetbrains.annotations.NotNull;
+import org.jetbrains.annotations.Nullable;
+import org.jglrxavpok.hephaistos.nbt.NBTCompound;
 
 import java.util.Collections;
 import java.util.HashSet;
@@ -19,10 +22,21 @@ import java.util.Set;
 public class ServerSender implements CommandSender {
 
     private final Set<Permission> permissions = Collections.unmodifiableSet(new HashSet<>());
+    private final NBTCompound nbtCompound = new NBTCompound();
 
     @NotNull
     @Override
     public Set<Permission> getAllPermissions() {
         return permissions;
     }
+
+    @Override
+    public <T> @Nullable T getTag(@NotNull Tag<T> tag) {
+        return tag.read(nbtCompound);
+    }
+
+    @Override
+    public <T> void setTag(@NotNull Tag<T> tag, @Nullable T value) {
+        tag.write(nbtCompound, value);
+    }
 }

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

@@ -1,6 +1,5 @@
 package net.minestom.server.command.builder;
 
-import com.google.common.annotations.Beta;
 import com.google.gson.JsonArray;
 import com.google.gson.JsonObject;
 import net.minestom.server.command.CommandSender;
@@ -10,6 +9,7 @@ import net.minestom.server.command.builder.arguments.ArgumentType;
 import net.minestom.server.command.builder.arguments.ArgumentWord;
 import net.minestom.server.command.builder.condition.CommandCondition;
 import net.minestom.server.utils.StringUtils;
+import org.jetbrains.annotations.ApiStatus;
 import org.jetbrains.annotations.NotNull;
 import org.jetbrains.annotations.Nullable;
 import org.slf4j.Logger;
@@ -221,7 +221,7 @@ public class Command {
      * @param format   the syntax format
      * @return the newly created {@link CommandSyntax syntaxes}.
      */
-    @Beta
+    @ApiStatus.Experimental
     public @NotNull Collection<CommandSyntax> addSyntax(@NotNull CommandExecutor executor, @NotNull String format) {
         return addSyntax(executor, ArgumentType.generate(format));
     }
@@ -302,7 +302,7 @@ public class Command {
     public void globalListener(@NotNull CommandSender sender, @NotNull CommandContext context, @NotNull String command) {
     }
 
-    @Beta
+    @ApiStatus.Experimental
     public @NotNull Set<String> getSyntaxesStrings() {
         Set<String> syntaxes = new HashSet<>();
 
@@ -320,7 +320,7 @@ public class Command {
         return syntaxes;
     }
 
-    @Beta
+    @ApiStatus.Experimental
     public @NotNull String getSyntaxesTree() {
         Node commandNode = new Node();
         commandNode.names.addAll(Arrays.asList(getNames()));

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

@@ -1,7 +1,7 @@
 package net.minestom.server.command.builder;
 
-import com.google.common.cache.Cache;
+import com.github.benmanes.caffeine.cache.Cache;
-import com.google.common.cache.CacheBuilder;
+import com.github.benmanes.caffeine.cache.Caffeine;
 import it.unimi.dsi.fastutil.ints.Int2ObjectRBTreeMap;
 import net.minestom.server.command.CommandSender;
 import net.minestom.server.command.builder.arguments.Argument;
@@ -25,7 +25,7 @@ public class CommandDispatcher {
     private final Map<String, Command> commandMap = new HashMap<>();
     private final Set<Command> commands = new HashSet<>();
 
-    private final Cache<String, CommandResult> cache = CacheBuilder.newBuilder()
+    private final Cache<String, CommandResult> cache = Caffeine.newBuilder()
             .expireAfterWrite(30, TimeUnit.SECONDS)
             .build();
 

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

@@ -1,6 +1,5 @@
 package net.minestom.server.command.builder.arguments;
 
-import com.google.common.annotations.Beta;
 import net.minestom.server.command.builder.ArgumentCallback;
 import net.minestom.server.command.builder.Command;
 import net.minestom.server.command.builder.CommandExecutor;
@@ -8,6 +7,7 @@ import net.minestom.server.command.builder.NodeMaker;
 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 org.jetbrains.annotations.ApiStatus;
 import org.jetbrains.annotations.NotNull;
 import org.jetbrains.annotations.Nullable;
 
@@ -210,8 +210,8 @@ public abstract class Argument<T> {
     /**
      * Gets the suggestion callback of the argument
      *
-     * @see #setSuggestionCallback
      * @return the suggestion callback of the argument, null if it doesn't exist
+     * @see #setSuggestionCallback
      */
     @Nullable
     public SuggestionCallback getSuggestionCallback() {
@@ -247,7 +247,7 @@ public abstract class Argument<T> {
      * @param <O>    The type of output expected.
      * @return A new ArgumentMap that can get this complex object type.
      */
-    @Beta
+    @ApiStatus.Experimental
     public <O> @NotNull ArgumentMap<T, O> map(@NotNull ArgumentMap.Mapper<T, O> mapper) {
         return new ArgumentMap<>(this, mapper);
     }

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

@@ -1,6 +1,5 @@
 package net.minestom.server.command.builder.arguments;
 
-import com.google.common.annotations.Beta;
 import net.minestom.server.MinecraftServer;
 import net.minestom.server.command.builder.CommandDispatcher;
 import net.minestom.server.command.builder.CommandResult;
@@ -8,6 +7,7 @@ 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 org.jetbrains.annotations.ApiStatus;
 import org.jetbrains.annotations.NotNull;
 
 public class ArgumentCommand extends Argument<CommandResult> {
@@ -69,7 +69,7 @@ public class ArgumentCommand extends Argument<CommandResult> {
         return shortcut;
     }
 
-    @Beta
+    @ApiStatus.Experimental
     public ArgumentCommand setShortcut(@NotNull String shortcut) {
         this.shortcut = shortcut;
         return this;

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

@@ -1,6 +1,5 @@
 package net.minestom.server.command.builder.arguments;
 
-import com.google.common.annotations.Beta;
 import net.minestom.server.command.builder.arguments.minecraft.*;
 import net.minestom.server.command.builder.arguments.minecraft.registry.*;
 import net.minestom.server.command.builder.arguments.number.ArgumentDouble;
@@ -11,6 +10,7 @@ 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.parser.ArgumentParser;
+import org.jetbrains.annotations.ApiStatus;
 import org.jetbrains.annotations.NotNull;
 
 /**
@@ -248,7 +248,7 @@ public class ArgumentType {
      * <p>
      * Note: this feature is in beta and is very likely to change depending on feedback.
      */
-    @Beta
+    @ApiStatus.Experimental
     public static Argument<?>[] generate(@NotNull String format) {
         return ArgumentParser.generate(format);
     }

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

@@ -1,6 +1,5 @@
 package net.minestom.server.command.builder.parser;
 
-import com.google.common.annotations.Beta;
 import net.minestom.server.command.builder.arguments.*;
 import net.minestom.server.command.builder.arguments.minecraft.*;
 import net.minestom.server.command.builder.arguments.minecraft.registry.*;
@@ -12,6 +11,7 @@ import net.minestom.server.command.builder.arguments.relative.ArgumentRelativeVe
 import net.minestom.server.command.builder.arguments.relative.ArgumentRelativeVec3;
 import net.minestom.server.command.builder.exception.ArgumentSyntaxException;
 import net.minestom.server.utils.StringUtils;
+import org.jetbrains.annotations.ApiStatus;
 import org.jetbrains.annotations.NotNull;
 import org.jetbrains.annotations.Nullable;
 
@@ -63,7 +63,7 @@ public class ArgumentParser {
         ARGUMENT_FUNCTION_MAP.put("relativevec2", ArgumentRelativeVec2::new);
     }
 
-    @Beta
+    @ApiStatus.Experimental
     public static @NotNull Argument<?>[] generate(@NotNull String format) {
         List<Argument<?>> result = new ArrayList<>();
 

src/main/java/net/minestom/server/data/DataContainer.java

@@ -6,7 +6,10 @@ import org.jetbrains.annotations.Nullable;
  * Represents an element which can have a {@link Data} attached to it.
  * <p>
  * The data will always be optional and can therefore be null.
+ *
+ * @deprecated switch to the Tag API instead
  */
+@Deprecated
 public interface DataContainer {
 
     /**
@@ -16,9 +19,10 @@ public interface DataContainer {
      * meaning that this will be null if no data has been defined.
      *
      * @return the {@link Data} of this container, can be null
+     * @deprecated use the tag API https://wiki.minestom.com/feature/tags
      */
-    @Nullable
+    @Deprecated
-    Data getData();
+    @Nullable Data getData();
 
     /**
      * Sets the {@link Data} of this container.
@@ -27,7 +31,8 @@ public interface DataContainer {
      * on your use-case.
      *
      * @param data the new {@link Data} of this container, null to remove it
+     * @deprecated use the tag API https://wiki.minestom.com/feature/tags
      */
+    @Deprecated
     void setData(@Nullable Data data);
-
 }

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

@@ -1,7 +1,5 @@
 package net.minestom.server.entity;
 
-import com.google.common.annotations.Beta;
-import com.google.common.collect.Queues;
 import net.kyori.adventure.sound.Sound;
 import net.kyori.adventure.text.Component;
 import net.kyori.adventure.text.event.HoverEvent;
@@ -35,6 +33,8 @@ import net.minestom.server.permission.PermissionHandler;
 import net.minestom.server.potion.Potion;
 import net.minestom.server.potion.PotionEffect;
 import net.minestom.server.potion.TimedPotion;
+import net.minestom.server.tag.Tag;
+import net.minestom.server.tag.TagHandler;
 import net.minestom.server.thread.ThreadProvider;
 import net.minestom.server.utils.BlockPosition;
 import net.minestom.server.utils.Position;
@@ -51,9 +51,11 @@ import net.minestom.server.utils.validate.Check;
 import org.jetbrains.annotations.ApiStatus;
 import org.jetbrains.annotations.NotNull;
 import org.jetbrains.annotations.Nullable;
+import org.jglrxavpok.hephaistos.nbt.NBTCompound;
 
 import java.util.*;
 import java.util.concurrent.ConcurrentHashMap;
+import java.util.concurrent.ConcurrentLinkedQueue;
 import java.util.concurrent.CopyOnWriteArrayList;
 import java.util.concurrent.CopyOnWriteArraySet;
 import java.util.concurrent.atomic.AtomicInteger;
@@ -65,7 +67,7 @@ import java.util.function.UnaryOperator;
  * <p>
  * To create your own entity you probably want to extends {@link LivingEntity} or {@link EntityCreature} instead.
  */
-public class Entity implements Viewable, Tickable, EventHandler<EntityEvent>, DataContainer, PermissionHandler, HoverEventSource<ShowEntity>, Sound.Emitter {
+public class Entity implements Viewable, Tickable, EventHandler<EntityEvent>, DataContainer, TagHandler, PermissionHandler, HoverEventSource<ShowEntity>, Sound.Emitter {
 
     private static final Map<Integer, Entity> ENTITY_BY_ID = new ConcurrentHashMap<>();
     private static final Map<UUID, Entity> ENTITY_BY_UUID = new ConcurrentHashMap<>();
@@ -93,9 +95,18 @@ public class Entity implements Viewable, Tickable, EventHandler<EntityEvent>, Da
     protected Vector velocity = new Vector(); // Movement in block per second
     protected boolean hasPhysics = true;
 
+    /**
+     * The amount of drag applied on the Y axle.
+     * <p>
+     * Unit: 1/tick
+     */
     protected double gravityDragPerTick;
+    /**
+     * Acceleration on the Y axle due to gravity
+     * <p>
+     * Unit: blocks/tick
+     */
     protected double gravityAcceleration;
-    protected double gravityTerminalVelocity;
     protected int gravityTickCount; // Number of tick where gravity tick was applied
 
     private boolean autoViewable;
@@ -103,6 +114,7 @@ public class Entity implements Viewable, Tickable, EventHandler<EntityEvent>, Da
     protected final Set<Player> viewers = ConcurrentHashMap.newKeySet();
     private final Set<Player> unmodifiableViewers = Collections.unmodifiableSet(viewers);
     private Data data;
+    private final NBTCompound nbtCompound = new NBTCompound();
     private final Set<Permission> permissions = new CopyOnWriteArraySet<>();
 
     protected UUID uuid;
@@ -128,7 +140,7 @@ public class Entity implements Viewable, Tickable, EventHandler<EntityEvent>, Da
     private final List<TimedPotion> effects = new CopyOnWriteArrayList<>();
 
     // list of scheduled tasks to be executed during the next entity tick
-    protected final Queue<Consumer<Entity>> nextTick = Queues.newConcurrentLinkedQueue();
+    protected final Queue<Consumer<Entity>> nextTick = new ConcurrentLinkedQueue<>();
 
     // Tick related
     private long ticks;
@@ -159,6 +171,8 @@ public class Entity implements Viewable, Tickable, EventHandler<EntityEvent>, Da
         Entity.ENTITY_BY_UUID.put(uuid, this);
 
         this.eventNode = EventNode.value("entity-" + uuid, EventFilter.ENTITY, this::equals);
+
+        initializeDefaultGravity();
     }
 
     public Entity(@NotNull EntityType entityType) {
@@ -524,13 +538,11 @@ public class Entity implements Viewable, Tickable, EventHandler<EntityEvent>, Da
                 Vector newVelocityOut = new Vector();
 
                 // Gravity force
-                final double gravityY = !hasNoGravity() ? Math.min(
+                final double gravityY = hasNoGravity() ? 0 : gravityAcceleration;
-                        gravityDragPerTick + (gravityAcceleration * (double) gravityTickCount),
-                        gravityTerminalVelocity) : 0;
 
                 final Vector deltaPos = new Vector(
                         getVelocity().getX() / tps,
-                        (getVelocity().getY() - gravityY) / tps,
+                        getVelocity().getY() / tps - gravityY,
                         getVelocity().getZ() / tps
                 );
 
@@ -591,6 +603,8 @@ public class Entity implements Viewable, Tickable, EventHandler<EntityEvent>, Da
 
                     this.velocity.setX(velocity.getX() * drag);
                     this.velocity.setZ(velocity.getZ() * drag);
+                    if (!hasNoGravity())
+                        this.velocity.setY(velocity.getY() * (1-gravityDragPerTick));
 
                     if (velocity.equals(new Vector())) {
                         this.velocity.zero();
@@ -982,15 +996,6 @@ public class Entity implements Viewable, Tickable, EventHandler<EntityEvent>, Da
         return gravityAcceleration;
     }
 
-    /**
-     * Gets the maximum gravity velocity.
-     *
-     * @return the maximum gravity velocity in block
-     */
-    public double getGravityTerminalVelocity() {
-        return gravityTerminalVelocity;
-    }
-
     /**
      * Gets the number of tick this entity has been applied gravity.
      *
@@ -1005,13 +1010,11 @@ public class Entity implements Viewable, Tickable, EventHandler<EntityEvent>, Da
      *
      * @param gravityDragPerTick      the gravity drag per tick in block
      * @param gravityAcceleration     the gravity acceleration in block
-     * @param gravityTerminalVelocity the gravity terminal velocity (maximum) in block
      * @see <a href="https://minecraft.gamepedia.com/Entity#Motion_of_entities">Entities motion</a>
      */
-    public void setGravity(double gravityDragPerTick, double gravityAcceleration, double gravityTerminalVelocity) {
+    public void setGravity(double gravityDragPerTick, double gravityAcceleration) {
         this.gravityDragPerTick = gravityDragPerTick;
         this.gravityAcceleration = gravityAcceleration;
-        this.gravityTerminalVelocity = gravityTerminalVelocity;
     }
 
     /**
@@ -1620,16 +1623,127 @@ public class Entity implements Viewable, Tickable, EventHandler<EntityEvent>, Da
         return Objects.requireNonNullElse(this.customSynchronizationCooldown, SYNCHRONIZATION_COOLDOWN);
     }
 
-    @Beta
+    @ApiStatus.Experimental
     public <T extends Entity> @NotNull Acquirable<T> getAcquirable() {
         return (Acquirable<T>) acquirable;
     }
 
-    @Beta
+    @ApiStatus.Experimental
     public <T extends Entity> @NotNull Acquirable<T> getAcquirable(@NotNull Class<T> clazz) {
         return (Acquirable<T>) acquirable;
     }
 
+    @Override
+    public <T> @Nullable T getTag(@NotNull Tag<T> tag) {
+        return tag.read(nbtCompound);
+    }
+
+    @Override
+    public <T> void setTag(@NotNull Tag<T> tag, @Nullable T value) {
+        tag.write(nbtCompound, value);
+    }
+
+    /**
+     * Sets the Entity's {@link gravityAcceleration} and {@link gravityDragPerTick} fields to
+     * the default values according to <a href="https://minecraft.fandom.com/wiki/Entity#Motion_of_entities">Motion of entities</a>
+     */
+    @SuppressWarnings("JavadocReference")
+    private void initializeDefaultGravity() {
+        // TODO Add support for these values in the data generator
+        // Acceleration
+        switch (entityType) {
+            // 0
+            case ITEM_FRAME:
+                this.gravityAcceleration = 0;
+                break;
+            // 0.03
+            case EGG:
+            case FISHING_BOBBER:
+            case EXPERIENCE_BOTTLE:
+            case ENDER_PEARL:
+            case POTION:
+            case SNOWBALL:
+                this.gravityAcceleration = 0.03;
+                break;
+            // 0.04
+            case BOAT:
+            case TNT:
+            case FALLING_BLOCK:
+            case ITEM:
+            case MINECART:
+                this.gravityAcceleration = 0.04;
+                break;
+            // 0.05
+            case ARROW:
+            case SPECTRAL_ARROW:
+            case TRIDENT:
+                this.gravityAcceleration = 0.05;
+                break;
+            // 0.06
+            case LLAMA_SPIT:
+                this.gravityAcceleration = 0.06;
+                break;
+            // 0.1
+            case FIREBALL:
+            case WITHER_SKULL:
+            case DRAGON_FIREBALL:
+                this.gravityAcceleration = 0.1;
+                break;
+            // 0.08
+            default:
+                this.gravityAcceleration = 0.08;
+                break;
+        }
+
+        // Drag
+        switch (entityType) {
+            // 0
+            case BOAT:
+                this.gravityDragPerTick = 0;
+                break;
+            // 0.01
+            case LLAMA_SPIT:
+            case ENDER_PEARL:
+            case POTION:
+            case SNOWBALL:
+            case EGG:
+            case TRIDENT:
+            case SPECTRAL_ARROW:
+            case ARROW:
+                this.gravityDragPerTick = 0.01;
+                break;
+            // 0.05
+            case MINECART:
+                this.gravityDragPerTick = 0.05;
+                break;
+            // 0.08
+            case FISHING_BOBBER:
+                this.gravityDragPerTick = 0.08;
+                break;
+            // 0.02
+            default:
+                this.gravityDragPerTick = 0.02;
+                break;
+        }
+    }
+
+    /**
+     * Applies knockback to the entity
+     *
+     * @param strength the strength of the knockback, 0.4 is the vanilla value for a bare hand hit
+     * @param x knockback on x axle, for default knockback use the following formula <pre>sin(attacker.yaw * (pi/180))</pre>
+     * @param z knockback on z axle, for default knockback use the following formula <pre>-cos(attacker.yaw * (pi/180))</pre>
+     */
+    public void takeKnockback(final float strength, final double x, final double z) {
+        if (strength > 0) {
+            //TODO check possible side effects of unnatural TPS (other than 20TPS)
+            final Vector velocityModifier = new Vector(x, 0d, z).normalize().multiply(strength * MinecraftServer.TICK_PER_SECOND / 2);
+            this.velocity.setX(velocity.getX() / 2d - velocityModifier.getX());
+            this.velocity.setY(onGround ? Math.min(.4d, velocity.getY() / 2d + strength) * MinecraftServer.TICK_PER_SECOND : velocity.getY());
+            this.velocity.setZ(velocity.getZ() / 2d - velocityModifier.getZ());
+        }
+    }
+
     public enum Pose {
         STANDING,
         FALL_FLYING,

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

@@ -47,7 +47,6 @@ public class EntityProjectile extends Entity {
         if (getEntityMeta() instanceof ProjectileMeta) {
             ((ProjectileMeta) getEntityMeta()).setShooter(this.shooter);
         }
-        setGravity(0.02f, 0.04f, 1.96f);
     }
 
     @Nullable

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

@@ -17,7 +17,6 @@ public class ExperienceOrb extends Entity {
 
     public ExperienceOrb(short experienceCount, @NotNull Position spawnPosition) {
         super(EntityType.EXPERIENCE_ORB, spawnPosition);
-        setGravity(0.02f, 0.04f, 1.96f);
         setBoundingBox(0.5f, 0.5f, 0.5f);
         //todo vanilla sets random velocity here?
         this.experienceCount = experienceCount;

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

@@ -43,7 +43,6 @@ public class ItemEntity extends Entity {
     public ItemEntity(@NotNull ItemStack itemStack, @NotNull Position spawnPosition) {
         super(EntityType.ITEM, spawnPosition);
         setItemStack(itemStack);
-        setGravity(0.02f, 0.04f, 1.96f);
         setBoundingBox(0.25f, 0.25f, 0.25f);
     }
 

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

@@ -90,7 +90,6 @@ public class LivingEntity extends Entity implements EquipmentHandler {
      */
     public LivingEntity(@NotNull EntityType entityType, @NotNull UUID uuid) {
         this(entityType, uuid, new Position());
-        setGravity(0.02f, 0.08f, 3.92f);
         initEquipments();
     }
 
@@ -104,7 +103,6 @@ public class LivingEntity extends Entity implements EquipmentHandler {
     @Deprecated
     public LivingEntity(@NotNull EntityType entityType, @NotNull UUID uuid, @NotNull Position spawnPosition) {
         super(entityType, uuid, spawnPosition);
-        setGravity(0.02f, 0.08f, 3.92f);
         initEquipments();
     }
 
@@ -781,4 +779,18 @@ public class LivingEntity extends Entity implements EquipmentHandler {
         return null;
     }
 
+    /**
+     * Applies knockback
+     * <p>
+     * Note: The strength is reduced based on knockback resistance
+     *
+     * @param strength the strength of the knockback, 0.4 is the vanilla value for a bare hand hit
+     * @param x knockback on x axle, for default knockback use the following formula <pre>sin(attacker.yaw * (pi/180))</pre>
+     * @param z knockback on z axle, for default knockback use the following formula <pre>-cos(attacker.yaw * (pi/180))</pre>
+     */
+    @Override
+    public void takeKnockback(float strength, final double x, final double z) {
+        strength *= 1 - getAttributeValue(Attribute.KNOCKBACK_RESISTANCE);
+        super.takeKnockback(strength, x, z);
+    }
 }

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

@@ -1,6 +1,5 @@
 package net.minestom.server.entity;
 
-import com.google.common.collect.Queues;
 import net.kyori.adventure.audience.MessageType;
 import net.kyori.adventure.bossbar.BossBar;
 import net.kyori.adventure.identity.Identified;
@@ -87,6 +86,7 @@ import org.jetbrains.annotations.Nullable;
 import java.nio.charset.StandardCharsets;
 import java.util.*;
 import java.util.concurrent.ConcurrentHashMap;
+import java.util.concurrent.ConcurrentLinkedQueue;
 import java.util.concurrent.atomic.AtomicInteger;
 import java.util.function.UnaryOperator;
 
@@ -119,7 +119,7 @@ public class Player extends LivingEntity implements CommandSender, Localizable,
     private final AtomicInteger teleportId = new AtomicInteger();
     private int receivedTeleportId;
 
-    private final Queue<ClientPlayPacket> packets = Queues.newConcurrentLinkedQueue();
+    private final Queue<ClientPlayPacket> packets = new ConcurrentLinkedQueue<>();
     private final boolean levelFlat;
     private final PlayerSettings settings;
     private float exp;
@@ -1379,9 +1379,7 @@ public class Player extends LivingEntity implements CommandSender, Localizable,
      * @param entity the entity to spectate
      */
     public void spectate(@NotNull Entity entity) {
-        CameraPacket cameraPacket = new CameraPacket();
+        playerConnection.sendPacket(new CameraPacket(entity));
-        cameraPacket.cameraId = entity.getEntityId();
-        playerConnection.sendPacket(cameraPacket);
     }
 
     /**

src/main/java/net/minestom/server/entity/ai/goal/DoNothingGoal.java

@@ -24,7 +24,7 @@ public class DoNothingGoal extends GoalSelector {
     public DoNothingGoal(EntityCreature entityCreature, long time, float chance) {
         super(entityCreature);
         this.time = time;
-        this.chance = MathUtils.clampFloat(chance, 0, 1);
+        this.chance = MathUtils.clamp(chance, 0, 1);
     }
 
     @Override

src/main/java/net/minestom/server/entity/damage/DamageType.java

@@ -8,8 +8,11 @@ import net.minestom.server.entity.Entity;
 import net.minestom.server.entity.LivingEntity;
 import net.minestom.server.entity.Player;
 import net.minestom.server.sound.SoundEvent;
+import net.minestom.server.tag.Tag;
+import net.minestom.server.tag.TagHandler;
 import org.jetbrains.annotations.NotNull;
 import org.jetbrains.annotations.Nullable;
+import org.jglrxavpok.hephaistos.nbt.NBTCompound;
 
 /**
  * Represents a type of damage, required when calling {@link LivingEntity#damage(DamageType, float)}
@@ -19,7 +22,7 @@ import org.jetbrains.annotations.Nullable;
  * Be aware that this class implements {@link DataContainer}
  * so you can add your own data to an already existing damage type without any wrapper.
  */
-public class DamageType implements DataContainer {
+public class DamageType implements TagHandler, DataContainer {
 
     public static final DamageType VOID = new DamageType("attack.outOfWorld");
     public static final DamageType GRAVITY = new DamageType("attack.fall");
@@ -30,6 +33,8 @@ public class DamageType implements DataContainer {
         }
     };
     private final String identifier;
+    private final Object nbtLock = new Object();
+    private final NBTCompound nbt = new NBTCompound();
     private Data data;
 
     /**
@@ -159,4 +164,18 @@ public class DamageType implements DataContainer {
     public void setData(Data data) {
         this.data = data;
     }
+
+    @Override
+    public <T> @Nullable T getTag(@NotNull Tag<T> tag) {
+        synchronized (nbtLock) {
+            return tag.read(nbt);
+        }
+    }
+
+    @Override
+    public <T> void setTag(@NotNull Tag<T> tag, @Nullable T value) {
+        synchronized (nbtLock) {
+            tag.write(nbt, value);
+        }
+    }
 }

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

@@ -29,6 +29,7 @@ import java.net.URL;
 import java.nio.file.Path;
 import java.util.*;
 import java.util.stream.Collectors;
+import java.util.zip.ZipEntry;
 import java.util.zip.ZipFile;
 
 public class ExtensionManager {
@@ -379,8 +380,14 @@ public class ExtensionManager {
      */
     @Nullable
     private DiscoveredExtension discoverFromJar(@NotNull File file) {
-        try (ZipFile f = new ZipFile(file);
+        try (ZipFile f = new ZipFile(file);) {
-             InputStreamReader reader = new InputStreamReader(f.getInputStream(f.getEntry("extension.json")))) {
+
+            ZipEntry entry = f.getEntry("extension.json");
+
+            if (entry == null)
+                throw new IllegalStateException("Missing extension.json in extension " + file.getName() + ".");
+
+            InputStreamReader reader = new InputStreamReader(f.getInputStream(entry));
 
             // Initialize DiscoveredExtension from GSON.
             DiscoveredExtension extension = GSON.fromJson(reader, DiscoveredExtension.class);

src/main/java/net/minestom/server/extras/velocity/VelocityProxy.java

@@ -1,7 +1,7 @@
 package net.minestom.server.extras.velocity;
 
-import com.google.common.net.InetAddresses;
 import io.netty.buffer.ByteBuf;
+import net.minestom.server.MinecraftServer;
 import net.minestom.server.entity.PlayerSkin;
 import net.minestom.server.utils.binary.BinaryReader;
 import org.jetbrains.annotations.NotNull;
@@ -9,6 +9,7 @@ import org.jetbrains.annotations.NotNull;
 import javax.crypto.Mac;
 import javax.crypto.spec.SecretKeySpec;
 import java.net.InetAddress;
+import java.net.UnknownHostException;
 import java.security.InvalidKeyException;
 import java.security.MessageDigest;
 import java.security.NoSuchAlgorithmException;
@@ -73,7 +74,12 @@ public final class VelocityProxy {
     }
 
     public static InetAddress readAddress(@NotNull BinaryReader reader) {
-        return InetAddresses.forString(reader.readSizedString());
+        try {
+            return InetAddress.getByName(reader.readSizedString());
+        } catch (UnknownHostException e) {
+            MinecraftServer.getExceptionManager().handleException(e);
+            return null;
+        }
     }
 
     public static PlayerSkin readSkin(@NotNull BinaryReader reader) {

src/main/java/net/minestom/server/instance/Chunk.java

@@ -16,6 +16,8 @@ import net.minestom.server.instance.block.CustomBlock;
 import net.minestom.server.network.packet.server.play.ChunkDataPacket;
 import net.minestom.server.network.packet.server.play.UpdateLightPacket;
 import net.minestom.server.network.player.PlayerConnection;
+import net.minestom.server.tag.Tag;
+import net.minestom.server.tag.TagHandler;
 import net.minestom.server.utils.PacketUtils;
 import net.minestom.server.utils.Position;
 import net.minestom.server.utils.binary.BinaryReader;
@@ -27,6 +29,7 @@ import net.minestom.server.world.biomes.Biome;
 import net.minestom.server.world.biomes.BiomeManager;
 import org.jetbrains.annotations.NotNull;
 import org.jetbrains.annotations.Nullable;
+import org.jglrxavpok.hephaistos.nbt.NBTCompound;
 
 import java.util.*;
 import java.util.concurrent.ConcurrentHashMap;
@@ -47,7 +50,7 @@ import java.util.concurrent.ConcurrentHashMap;
  * You generally want to avoid storing references of this object as this could lead to a huge memory leak,
  * you should store the chunk coordinates instead.
  */
-public abstract class Chunk implements Viewable, Tickable, DataContainer {
+public abstract class Chunk implements Viewable, Tickable, TagHandler, DataContainer {
 
     protected static final BlockManager BLOCK_MANAGER = MinecraftServer.getBlockManager();
     protected static final BiomeManager BIOME_MANAGER = MinecraftServer.getBiomeManager();
@@ -75,6 +78,7 @@ public abstract class Chunk implements Viewable, Tickable, DataContainer {
     protected PFColumnarSpace columnarSpace;
 
     // Data
+    private final NBTCompound nbt = new NBTCompound();
     protected Data data;
 
     public Chunk(@NotNull Instance instance, @Nullable Biome[] biomes, int chunkX, int chunkZ, boolean shouldGenerate) {
@@ -480,6 +484,16 @@ public abstract class Chunk implements Viewable, Tickable, DataContainer {
         return unmodifiableViewers;
     }
 
+    @Override
+    public <T> @Nullable T getTag(@NotNull Tag<T> tag) {
+        return tag.read(nbt);
+    }
+
+    @Override
+    public <T> void setTag(@NotNull Tag<T> tag, @Nullable T value) {
+        tag.write(nbt, value);
+    }
+
     @Nullable
     @Override
     public Data getData() {

src/main/java/net/minestom/server/instance/Instance.java

@@ -1,6 +1,5 @@
 package net.minestom.server.instance;
 
-import com.google.common.collect.Queues;
 import net.kyori.adventure.identity.Identity;
 import net.kyori.adventure.pointer.Pointers;
 import net.minestom.server.MinecraftServer;
@@ -29,6 +28,8 @@ import net.minestom.server.instance.block.CustomBlock;
 import net.minestom.server.network.packet.server.play.BlockActionPacket;
 import net.minestom.server.network.packet.server.play.TimeUpdatePacket;
 import net.minestom.server.storage.StorageLocation;
+import net.minestom.server.tag.Tag;
+import net.minestom.server.tag.TagHandler;
 import net.minestom.server.thread.ThreadProvider;
 import net.minestom.server.utils.BlockPosition;
 import net.minestom.server.utils.PacketUtils;
@@ -44,9 +45,11 @@ import net.minestom.server.world.DimensionType;
 import org.jetbrains.annotations.ApiStatus;
 import org.jetbrains.annotations.NotNull;
 import org.jetbrains.annotations.Nullable;
+import org.jglrxavpok.hephaistos.nbt.NBTCompound;
 
 import java.util.*;
 import java.util.concurrent.ConcurrentHashMap;
+import java.util.concurrent.ConcurrentLinkedQueue;
 import java.util.function.Consumer;
 
 /**
@@ -60,7 +63,7 @@ import java.util.function.Consumer;
  * you need to be sure to signal the {@link UpdateManager} of the changes using
  * {@link UpdateManager#signalChunkLoad(Chunk)} and {@link UpdateManager#signalChunkUnload(Chunk)}.
  */
-public abstract class Instance implements BlockModifier, Tickable, EventHandler<InstanceEvent>, DataContainer, PacketGroupingAudience {
+public abstract class Instance implements BlockModifier, Tickable, TagHandler, PacketGroupingAudience, EventHandler<InstanceEvent>, DataContainer {
 
     protected static final BlockManager BLOCK_MANAGER = MinecraftServer.getBlockManager();
     protected static final UpdateManager UPDATE_MANAGER = MinecraftServer.getUpdateManager();
@@ -98,9 +101,11 @@ public abstract class Instance implements BlockModifier, Tickable, EventHandler<
     protected UUID uniqueId;
 
     // list of scheduled tasks to be executed during the next instance tick
-    protected final Queue<Consumer<Instance>> nextTick = Queues.newConcurrentLinkedQueue();
+    protected final Queue<Consumer<Instance>> nextTick = new ConcurrentLinkedQueue<>();
 
     // instance custom data
+    private final Object nbtLock = new Object();
+    private final NBTCompound nbt = new NBTCompound();
     private Data data;
 
     // the explosion supplier
@@ -1061,6 +1066,20 @@ public abstract class Instance implements BlockModifier, Tickable, EventHandler<
         this.worldBorder.update();
     }
 
+    @Override
+    public <T> @Nullable T getTag(@NotNull Tag<T> tag) {
+        synchronized (nbtLock) {
+            return tag.read(nbt);
+        }
+    }
+
+    @Override
+    public <T> void setTag(@NotNull Tag<T> tag, @Nullable T value) {
+        synchronized (nbtLock) {
+            tag.write(nbt, value);
+        }
+    }
+
     /**
      * Creates an explosion at the given position with the given strength.
      * The algorithm used to compute damages is provided by {@link #getExplosionSupplier()}.

src/main/java/net/minestom/server/instance/InstanceContainer.java

@@ -750,10 +750,7 @@ public class InstanceContainer extends Instance {
      * @param blockStateId  the new state of the block
      */
     private void sendBlockChange(@NotNull Chunk chunk, @NotNull BlockPosition blockPosition, short blockStateId) {
-        BlockChangePacket blockChangePacket = new BlockChangePacket();
+        chunk.sendPacketToViewers(new BlockChangePacket(blockPosition, blockStateId));
-        blockChangePacket.blockPosition = blockPosition;
-        blockChangePacket.blockStateId = blockStateId;
-        chunk.sendPacketToViewers(blockChangePacket);
     }
 
     @Override

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

@@ -5,10 +5,13 @@ import net.minestom.server.data.DataContainer;
 import net.minestom.server.inventory.click.InventoryClickProcessor;
 import net.minestom.server.inventory.condition.InventoryCondition;
 import net.minestom.server.item.ItemStack;
+import net.minestom.server.tag.Tag;
+import net.minestom.server.tag.TagHandler;
 import net.minestom.server.utils.MathUtils;
 import net.minestom.server.utils.validate.Check;
 import org.jetbrains.annotations.NotNull;
 import org.jetbrains.annotations.Nullable;
+import org.jglrxavpok.hephaistos.nbt.NBTCompound;
 
 import java.util.ArrayList;
 import java.util.Arrays;
@@ -19,7 +22,7 @@ import java.util.function.UnaryOperator;
 /**
  * Represents an inventory where items can be modified/retrieved.
  */
-public abstract class AbstractInventory implements InventoryClickHandler, DataContainer {
+public abstract class AbstractInventory implements InventoryClickHandler, TagHandler, DataContainer {
 
     private final int size;
     protected final ItemStack[] itemStacks;
@@ -29,6 +32,8 @@ public abstract class AbstractInventory implements InventoryClickHandler, DataCo
     // the click processor which process all the clicks in the inventory
     protected final InventoryClickProcessor clickProcessor = new InventoryClickProcessor();
 
+    private final Object nbtLock = new Object();
+    private final NBTCompound nbt = new NBTCompound();
     private Data data;
 
     protected AbstractInventory(int size) {
@@ -210,6 +215,20 @@ public abstract class AbstractInventory implements InventoryClickHandler, DataCo
         }
     }
 
+    @Override
+    public <T> @Nullable T getTag(@NotNull Tag<T> tag) {
+        synchronized (nbtLock) {
+            return tag.read(nbt);
+        }
+    }
+
+    @Override
+    public <T> void setTag(@NotNull Tag<T> tag, @Nullable T value) {
+        synchronized (nbtLock) {
+            tag.write(nbt, value);
+        }
+    }
+
     @Override
     public @Nullable Data getData() {
         return data;

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

@@ -403,16 +403,11 @@ public class PlayerInventory extends AbstractInventory implements EquipmentHandl
     public boolean doubleClick(@NotNull Player player, int slot) {
         final ItemStack cursor = getCursorItem();
         final InventoryClickResult clickResult = clickProcessor.doubleClick(this, null, player, slot, cursor);
-
         if (clickResult == null)
             return false;
-
         if (clickResult.doRefresh())
             update();
-
-        setItemStack(slot, OFFSET, clickResult.getClicked());
         setCursorItem(clickResult.getCursor());
-
         return !clickResult.isCancel();
     }
 }

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

@@ -51,7 +51,7 @@ public class ItemMeta implements TagReadable, Writeable {
         this.canDestroy = new HashSet<>(metaBuilder.canDestroy);
         this.canPlaceOn = new HashSet<>(metaBuilder.canPlaceOn);
 
-        this.nbt = metaBuilder.nbt;
+        this.nbt = metaBuilder.nbt();
         this.emptyBuilder = metaBuilder.getSupplier().get();
     }
 
@@ -117,11 +117,6 @@ public class ItemMeta implements TagReadable, Writeable {
         return tag.read(nbt);
     }
 
-    @Override
-    public boolean hasTag(@NotNull Tag<?> tag) {
-        return nbt.containsKey(tag.getKey());
-    }
-
     public @NotNull NBTCompound toNBT() {
         return nbt.deepClone();
     }
@@ -169,12 +164,7 @@ public class ItemMeta implements TagReadable, Writeable {
     @Deprecated
     @Contract(pure = true)
     public <T> T getOrDefault(@NotNull Tag<T> tag, @Nullable T defaultValue) {
-        var key = tag.getKey();
+        return tag.defaultValue(defaultValue).read(toNBT());
-        if (nbt.containsKey(key)) {
-            return tag.read(toNBT());
-        } else {
-            return defaultValue;
-        }
     }
 
     /**

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

@@ -2,7 +2,6 @@ package net.minestom.server.item;
 
 import net.kyori.adventure.text.Component;
 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;
@@ -15,12 +14,17 @@ import org.jetbrains.annotations.Nullable;
 import org.jglrxavpok.hephaistos.nbt.*;
 
 import java.util.*;
+import java.util.concurrent.atomic.AtomicReferenceFieldUpdater;
 import java.util.function.Consumer;
 import java.util.function.Supplier;
 
 public abstract class ItemMetaBuilder implements TagWritable {
 
-    protected NBTCompound nbt = new NBTCompound();
+    private static final AtomicReferenceFieldUpdater<ItemMetaBuilder, NBTCompound> NBT_UPDATER =
+            AtomicReferenceFieldUpdater.newUpdater(ItemMetaBuilder.class, NBTCompound.class, "nbt");
+
+    protected volatile boolean built = false;
+    private volatile NBTCompound nbt = new NBTCompound();
 
     protected int damage;
     protected boolean unbreakable;
@@ -36,21 +40,21 @@ public abstract class ItemMetaBuilder implements TagWritable {
     @Contract("_ -> this")
     public @NotNull ItemMetaBuilder damage(int damage) {
         this.damage = damage;
-        this.nbt.setInt("Damage", damage);
+        mutateNbt(compound -> compound.setInt("Damage", damage));
         return this;
     }
 
     @Contract("_ -> this")
     public @NotNull ItemMetaBuilder unbreakable(boolean unbreakable) {
         this.unbreakable = unbreakable;
-        this.nbt.setByte("Unbreakable", (byte) (unbreakable ? 1 : 0));
+        mutateNbt(compound -> compound.setByte("Unbreakable", (byte) (unbreakable ? 1 : 0)));
         return this;
     }
 
     @Contract("_ -> this")
     public @NotNull ItemMetaBuilder hideFlag(int hideFlag) {
         this.hideFlag = hideFlag;
-        this.nbt.setInt("HideFlags", hideFlag);
+        mutateNbt(compound -> compound.setInt("HideFlags", hideFlag));
         return this;
     }
 
@@ -79,7 +83,7 @@ public abstract class ItemMetaBuilder implements TagWritable {
 
     @Contract("_ -> this")
     public @NotNull ItemMetaBuilder lore(@NotNull List<@NotNull Component> lore) {
-        this.lore = lore;
+        this.lore = new ArrayList<>(lore);
         handleCompound("display", nbtCompound -> {
             final NBTList<NBTString> loreNBT = new NBTList<>(NBTTypes.TAG_String);
             for (Component line : lore) {
@@ -98,8 +102,8 @@ public abstract class ItemMetaBuilder implements TagWritable {
 
     @Contract("_ -> this")
     public @NotNull ItemMetaBuilder enchantments(@NotNull Map<Enchantment, Short> enchantments) {
-        this.enchantmentMap = enchantments;
+        this.enchantmentMap = new HashMap<>(enchantments);
-        handleMap(enchantmentMap, "Enchantments", nbt, () -> {
+        handleMap(enchantmentMap, "Enchantments", () -> {
             NBTUtils.writeEnchant(nbt, "Enchantments", enchantmentMap);
             return nbt.get("Enchantments");
         });
@@ -115,16 +119,16 @@ public abstract class ItemMetaBuilder implements TagWritable {
 
     @Contract("-> this")
     public @NotNull ItemMetaBuilder clearEnchantment() {
-        this.enchantmentMap.clear();
+        this.enchantmentMap = Collections.emptyMap();
         enchantments(enchantmentMap);
         return this;
     }
 
     @Contract("_ -> this")
     public @NotNull ItemMetaBuilder attributes(@NotNull List<@NotNull ItemAttribute> attributes) {
-        this.attributes = attributes;
+        this.attributes = new ArrayList<>(attributes);
 
-        handleCollection(attributes, "AttributeModifiers", nbt, () -> {
+        handleCollection(attributes, "AttributeModifiers", () -> {
             NBTList<NBTCompound> attributesNBT = new NBTList<>(NBTTypes.TAG_Compound);
             for (ItemAttribute itemAttribute : attributes) {
                 final UUID uuid = itemAttribute.getUuid();
@@ -147,17 +151,16 @@ public abstract class ItemMetaBuilder implements TagWritable {
     @Contract("_ -> this")
     public @NotNull ItemMetaBuilder customModelData(int customModelData) {
         this.customModelData = customModelData;
-        this.nbt.setInt("CustomModelData", customModelData);
+        mutateNbt(compound -> compound.setInt("CustomModelData", customModelData));
         return this;
     }
 
     @Contract("_ -> this")
     public @NotNull ItemMetaBuilder canPlaceOn(@NotNull Set<@NotNull Block> blocks) {
-        this.canPlaceOn = blocks;
+        this.canPlaceOn = new HashSet<>(blocks);
-        handleCollection(canPlaceOn, "CanPlaceOn", nbt, () -> {
+        handleCollection(canPlaceOn, "CanPlaceOn", () -> {
             NBTList<NBTString> list = new NBTList<>(NBTTypes.TAG_String);
             canPlaceOn.forEach(block -> list.add(new NBTString(block.getName())));
-            nbt.set("CanPlaceOn", list);
             return list;
         });
         return this;
@@ -170,11 +173,10 @@ public abstract class ItemMetaBuilder implements TagWritable {
 
     @Contract("_ -> this")
     public @NotNull ItemMetaBuilder canDestroy(@NotNull Set<@NotNull Block> blocks) {
-        this.canDestroy = blocks;
+        this.canDestroy = new HashSet<>(blocks);
-        handleCollection(canDestroy, "CanDestroy", nbt, () -> {
+        handleCollection(canDestroy, "CanDestroy", () -> {
             NBTList<NBTString> list = new NBTList<>(NBTTypes.TAG_String);
             canDestroy.forEach(block -> list.add(new NBTString(block.getName())));
-            nbt.set("CanDestroy", list);
             return list;
         });
         return this;
@@ -187,7 +189,7 @@ public abstract class ItemMetaBuilder implements TagWritable {
 
     @Override
     public <T> void setTag(@NotNull Tag<T> tag, @Nullable T value) {
-        tag.write(nbt, value);
+        mutateNbt(compound -> tag.write(compound, value));
     }
 
     public <T> @NotNull ItemMetaBuilder set(@NotNull Tag<T> tag, @Nullable T value) {
@@ -202,8 +204,27 @@ public abstract class ItemMetaBuilder implements TagWritable {
 
     protected abstract @NotNull Supplier<@NotNull ItemMetaBuilder> getSupplier();
 
+    protected synchronized void mutateNbt(Consumer<NBTCompound> consumer) {
+        if (built) {
+            built = false;
+            final var currentNbt = nbt;
+            NBT_UPDATER.compareAndSet(this, currentNbt, currentNbt.deepClone());
+        }
+        consumer.accept(nbt);
+    }
+
+    protected synchronized NBTCompound nbt() {
+        return nbt;
+    }
+
+    protected @NotNull ItemMeta generate() {
+        this.built = true;
+        return build();
+    }
+
     protected void handleCompound(@NotNull String key,
                                   @NotNull Consumer<@NotNull NBTCompound> consumer) {
+        mutateNbt(nbt -> {
             NBTCompound compound = null;
             boolean newNbt = false;
             if (nbt.containsKey(key)) {
@@ -224,41 +245,44 @@ public abstract class ItemMetaBuilder implements TagWritable {
                 } else if (!newNbt && compound.getSize() == 0) {
                     this.nbt.removeTag(key);
                 }
-
             }
+        });
     }
 
     protected void handleNullable(@Nullable Object value,
                                   @NotNull String key,
-                                  @NotNull NBTCompound nbtCompound,
                                   @NotNull Supplier<@NotNull NBT> supplier) {
+        mutateNbt(compound -> {
             if (value != null) {
-            nbtCompound.set(key, supplier.get());
+                compound.set(key, supplier.get());
             } else {
-            nbtCompound.removeTag(key);
+                compound.removeTag(key);
             }
+        });
     }
 
     protected void handleCollection(@NotNull Collection<?> objects,
                                     @NotNull String key,
-                                    @NotNull NBTCompound nbtCompound,
                                     @NotNull Supplier<@NotNull NBT> supplier) {
+        mutateNbt(compound -> {
             if (!objects.isEmpty()) {
-            nbtCompound.set(key, supplier.get());
+                compound.set(key, supplier.get());
             } else {
-            nbtCompound.removeTag(key);
+                compound.removeTag(key);
             }
+        });
     }
 
     protected void handleMap(@NotNull Map<?, ?> objects,
                              @NotNull String key,
-                             @NotNull NBTCompound nbtCompound,
                              @NotNull Supplier<@NotNull NBT> supplier) {
+        mutateNbt(compound -> {
             if (!objects.isEmpty()) {
-            nbtCompound.set(key, supplier.get());
+                compound.set(key, supplier.get());
             } else {
-            nbtCompound.removeTag(key);
+                compound.removeTag(key);
             }
+        });
     }
 
     @Contract(value = "_, _ -> new", pure = true)
@@ -271,5 +295,4 @@ public abstract class ItemMetaBuilder implements TagWritable {
 
     public interface Provider<T extends ItemMetaBuilder> {
     }
-
 }

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

@@ -203,11 +203,6 @@ public final class ItemStack implements TagReadable, HoverEventSource<HoverEvent
         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/ItemStackBuilder.java

@@ -1,8 +1,8 @@
 package net.minestom.server.item;
 
-import com.google.common.annotations.Beta;
 import net.kyori.adventure.text.Component;
 import net.minestom.server.item.metadata.*;
+import org.jetbrains.annotations.ApiStatus;
 import org.jetbrains.annotations.Contract;
 import org.jetbrains.annotations.NotNull;
 import org.jetbrains.annotations.Nullable;
@@ -100,7 +100,7 @@ public class ItemStackBuilder {
         return this;
     }
 
-    @Beta
+    @ApiStatus.Experimental
     @Contract(value = "_ -> this")
     public @NotNull ItemStackBuilder stackingRule(@Nullable StackingRule stackingRule) {
         this.stackingRule = stackingRule;
@@ -109,9 +109,9 @@ public class ItemStackBuilder {
 
     @Contract(value = "-> new", pure = true)
     public @NotNull ItemStack build() {
-        if (amount > 0)
+        if (amount < 1)
-            return new ItemStack(material, amount, metaBuilder.build(), stackingRule);
             return ItemStack.AIR;
+        return new ItemStack(material, amount, metaBuilder.generate(), stackingRule);
     }
 
     private static final class DefaultMeta extends ItemMetaBuilder {
@@ -130,5 +130,4 @@ public class ItemStackBuilder {
             return DefaultMeta::new;
         }
     }
-
 }

src/main/java/net/minestom/server/item/metadata/CompassMeta.java

@@ -45,18 +45,20 @@ public class CompassMeta extends ItemMeta implements ItemMetaBuilder.Provider<Co
 
         public Builder lodestoneTracked(boolean lodestoneTracked) {
             this.lodestoneTracked = lodestoneTracked;
-            this.nbt.setByte("LodestoneTracked", (byte) (lodestoneTracked ? 1 : 0));
+            mutateNbt(compound -> compound.setByte("LodestoneTracked", (byte) (lodestoneTracked ? 1 : 0)));
             return this;
         }
 
         public Builder lodestoneDimension(@Nullable String lodestoneDimension) {
             this.lodestoneDimension = lodestoneDimension;
 
+            mutateNbt(compound -> {
                 if (lodestoneDimension != null) {
-                this.nbt.setString("LodestoneDimension", lodestoneDimension);
+                    compound.setString("LodestoneDimension", lodestoneDimension);
                 } else {
-                this.nbt.removeTag("LodestoneDimension");
+                    compound.removeTag("LodestoneDimension");
                 }
+            });
 
             return this;
         }
@@ -64,15 +66,17 @@ public class CompassMeta extends ItemMeta implements ItemMetaBuilder.Provider<Co
         public Builder lodestonePosition(@Nullable Position lodestonePosition) {
             this.lodestonePosition = lodestonePosition;
 
+            mutateNbt(compound -> {
                 if (lodestonePosition != null) {
                     NBTCompound posCompound = new NBTCompound();
                     posCompound.setInt("X", (int) lodestonePosition.getX());
                     posCompound.setInt("Y", (int) lodestonePosition.getY());
                     posCompound.setInt("Z", (int) lodestonePosition.getZ());
-                this.nbt.set("LodestonePos", posCompound);
+                    compound.set("LodestonePos", posCompound);
                 } else {
-                this.nbt.removeTag("LodestonePos");
+                    compound.removeTag("LodestonePos");
                 }
+            });
 
             return this;
         }

src/main/java/net/minestom/server/item/metadata/CrossbowMeta.java

@@ -97,7 +97,7 @@ public class CrossbowMeta extends ItemMeta implements ItemMetaBuilder.Provider<S
             if (!projectile.isAir()) {
                 chargedProjectiles.add(getItemCompound(projectile));
             }
-            this.nbt.set("ChargedProjectiles", chargedProjectiles);
+            mutateNbt(compound -> compound.set("ChargedProjectiles", chargedProjectiles));
 
             return this;
         }
@@ -123,7 +123,7 @@ public class CrossbowMeta extends ItemMeta implements ItemMetaBuilder.Provider<S
             chargedProjectiles.add(getItemCompound(projectile1));
             chargedProjectiles.add(getItemCompound(projectile2));
             chargedProjectiles.add(getItemCompound(projectile3));
-            this.nbt.set("ChargedProjectiles", chargedProjectiles);
+            mutateNbt(compound -> compound.set("ChargedProjectiles", chargedProjectiles));
 
             return this;
         }
@@ -135,7 +135,7 @@ public class CrossbowMeta extends ItemMeta implements ItemMetaBuilder.Provider<S
          */
         public Builder charged(boolean charged) {
             this.charged = charged;
-            this.nbt.setByte("Charged", (byte) (charged ? 1 : 0));
+            mutateNbt(compound -> compound.setByte("Charged", (byte) (charged ? 1 : 0)));
             return this;
         }
 

src/main/java/net/minestom/server/item/metadata/EnchantedBookMeta.java

@@ -35,13 +35,13 @@ public class EnchantedBookMeta extends ItemMeta implements ItemMetaBuilder.Provi
 
         private Map<Enchantment, Short> enchantments = new HashMap<>();
 
-        public @NotNull Builder enchantments(Map<Enchantment, Short> enchantments) {
+        public @NotNull Builder enchantments(@NotNull Map<Enchantment, Short> enchantments) {
             this.enchantments = enchantments;
-            NBTUtils.writeEnchant(nbt, "StoredEnchantments", enchantments);
+            mutateNbt(compound -> NBTUtils.writeEnchant(compound, "StoredEnchantments", enchantments));
             return this;
         }
 
-        public @NotNull Builder enchantment(Enchantment enchantment, short level) {
+        public @NotNull Builder enchantment(@NotNull Enchantment enchantment, short level) {
             this.enchantments.put(enchantment, level);
             enchantments(enchantments);
             return this;

src/main/java/net/minestom/server/item/metadata/FireworkEffectMeta.java

@@ -28,7 +28,7 @@ public class FireworkEffectMeta extends ItemMeta implements ItemMetaBuilder.Prov
 
         public Builder effect(@Nullable FireworkEffect fireworkEffect) {
             this.fireworkEffect = fireworkEffect;
-            this.nbt.set("Explosion", this.fireworkEffect.asCompound());
+            mutateNbt(compound -> compound.set("Explosion", this.fireworkEffect.asCompound()));
             return this;
         }
 

src/main/java/net/minestom/server/item/metadata/MapMeta.java

@@ -91,18 +91,18 @@ public class MapMeta extends ItemMeta implements ItemMetaBuilder.Provider<MapMet
 
         public Builder mapId(int value) {
             this.mapId = value;
-            this.nbt.setInt("map", mapId);
+            mutateNbt(compound -> compound.setInt("map", mapId));
             return this;
         }
 
         public Builder mapScaleDirection(int value) {
             this.mapScaleDirection = value;
-            this.nbt.setInt("map_scale_direction", value);
+            mutateNbt(compound -> compound.setInt("map_scale_direction", value));
             return this;
         }
 
         public Builder decorations(List<MapDecoration> value) {
-            this.decorations = value;
+            this.decorations = new ArrayList<>(value);
 
             NBTList<NBTCompound> decorationsList = new NBTList<>(NBTTypes.TAG_Compound);
             for (MapDecoration decoration : decorations) {
@@ -115,7 +115,7 @@ public class MapMeta extends ItemMeta implements ItemMetaBuilder.Provider<MapMet
 
                 decorationsList.add(decorationCompound);
             }
-            this.nbt.set("Decorations", decorationsList);
+            mutateNbt(compound -> compound.set("Decorations", decorationsList));
 
             return this;
         }
@@ -123,14 +123,16 @@ public class MapMeta extends ItemMeta implements ItemMetaBuilder.Provider<MapMet
         public Builder mapColor(Color value) {
             this.mapColor = value;
 
+            mutateNbt(nbt -> {
                 NBTCompound displayCompound;
                 if (nbt.containsKey("display")) {
                     displayCompound = nbt.getCompound("display");
                 } else {
                     displayCompound = new NBTCompound();
-                this.nbt.set("display", displayCompound);
+                    nbt.set("display", displayCompound);
                 }
                 displayCompound.setInt("MapColor", mapColor.asRGB());
+            });
 
             return this;
         }

src/main/java/net/minestom/server/item/metadata/PotionMeta.java

@@ -52,7 +52,7 @@ public class PotionMeta extends ItemMeta implements ItemMetaBuilder.Provider<Pot
 
         public Builder potionType(@NotNull PotionType potionType) {
             this.potionType = potionType;
-            this.nbt.setString("Potion", potionType.getNamespaceID().asString());
+            mutateNbt(compound -> compound.setString("Potion", potionType.getNamespaceID().asString()));
             return this;
         }
 
@@ -71,14 +71,14 @@ public class PotionMeta extends ItemMeta implements ItemMetaBuilder.Provider<Pot
 
                 potionList.add(potionCompound);
             }
-            this.nbt.set("CustomPotionEffects", potionList);
+            mutateNbt(compound -> compound.set("CustomPotionEffects", potionList));
 
             return this;
         }
 
         public Builder color(@NotNull Color color) {
             this.color = color;
-            this.nbt.setInt("CustomPotionColor", color.asRGB());
+            mutateNbt(compound -> compound.setInt("CustomPotionColor", color.asRGB()));
             return this;
         }
 

src/main/java/net/minestom/server/item/metadata/WritableBookMeta.java

@@ -2,7 +2,6 @@ package net.minestom.server.item.metadata;
 
 import net.kyori.adventure.text.Component;
 import net.kyori.adventure.text.serializer.gson.GsonComponentSerializer;
-import net.minestom.server.adventure.AdventureSerializer;
 import net.minestom.server.item.ItemMeta;
 import net.minestom.server.item.ItemMetaBuilder;
 import org.jetbrains.annotations.NotNull;
@@ -53,22 +52,22 @@ public class WritableBookMeta extends ItemMeta implements ItemMetaBuilder.Provid
 
         public Builder author(@Nullable String author) {
             this.author = author;
-            handleNullable(author, "author", nbt,
+            handleNullable(author, "author",
                     () -> new NBTString(Objects.requireNonNull(author)));
             return this;
         }
 
         public Builder title(@Nullable String title) {
             this.title = title;
-            handleNullable(title, "title", nbt,
+            handleNullable(title, "title",
                     () -> new NBTString(Objects.requireNonNull(title)));
             return this;
         }
 
         public Builder pages(@NotNull List<@NotNull Component> pages) {
-            this.pages = pages;
+            this.pages = new ArrayList<>(pages);
 
-            handleCollection(pages, "pages", nbt, () -> {
+            handleCollection(pages, "pages", () -> {
                 NBTList<NBTString> list = new NBTList<>(NBTTypes.TAG_String);
                 for (Component page : pages) {
                     list.add(new NBTString(GsonComponentSerializer.gson().serialize(page)));

src/main/java/net/minestom/server/item/metadata/WrittenBookMeta.java

@@ -86,35 +86,35 @@ public class WrittenBookMeta extends ItemMeta implements ItemMetaBuilder.Provide
 
         public Builder resolved(boolean resolved) {
             this.resolved = resolved;
-            this.nbt.setByte("resolved", (byte) (resolved ? 1 : 0));
+            mutateNbt(compound -> compound.setByte("resolved", (byte) (resolved ? 1 : 0)));
             return this;
         }
 
         public Builder generation(@Nullable WrittenBookGeneration generation) {
             this.generation = generation;
-            handleNullable(generation, "generation", nbt,
+            handleNullable(generation, "generation",
                     () -> new NBTInt(Objects.requireNonNull(generation).ordinal()));
             return this;
         }
 
         public Builder author(@Nullable String author) {
             this.author = author;
-            handleNullable(author, "author", nbt,
+            handleNullable(author, "author",
                     () -> new NBTString(Objects.requireNonNull(author)));
             return this;
         }
 
         public Builder title(@Nullable String title) {
             this.title = title;
-            handleNullable(title, "title", nbt,
+            handleNullable(title, "title",
                     () -> new NBTString(Objects.requireNonNull(title)));
             return this;
         }
 
         public Builder pages(@NotNull List<@NotNull Component> pages) {
-            this.pages = pages;
+            this.pages = new ArrayList<>(pages);
 
-            handleCollection(pages, "pages", nbt, () -> {
+            handleCollection(pages, "pages", () -> {
                 NBTList<NBTString> list = new NBTList<>(NBTTypes.TAG_String);
                 for (Component page : pages) {
                     list.add(new NBTString(GsonComponentSerializer.gson().serialize(page)));

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

@@ -104,10 +104,7 @@ public class BlockPlacementListener {
                 //Send a block change with AIR as block to keep the client in sync,
                 //using refreshChunk results in the client not being in sync
                 //after rapid invalid block placements
-                BlockChangePacket blockChangePacket = new BlockChangePacket();
+                player.getPlayerConnection().sendPacket(new BlockChangePacket(blockPosition, Block.AIR.getBlockId()));
-                blockChangePacket.blockPosition = blockPosition;
-                blockChangePacket.blockStateId = Block.AIR.getBlockId();
-                player.getPlayerConnection().sendPacket(blockChangePacket);
             }
             return;
         }

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

@@ -263,13 +263,6 @@ public class PlayerDiggingListener {
      */
     private static void sendAcknowledgePacket(@NotNull Player player, @NotNull BlockPosition blockPosition, int blockStateId,
                                               @NotNull ClientPlayerDiggingPacket.Status status, boolean success) {
-        AcknowledgePlayerDiggingPacket acknowledgePlayerDiggingPacket = new AcknowledgePlayerDiggingPacket();
+        player.getPlayerConnection().sendPacket(new AcknowledgePlayerDiggingPacket(blockPosition, blockStateId, status, success));
-        acknowledgePlayerDiggingPacket.blockPosition = blockPosition;
-        acknowledgePlayerDiggingPacket.blockStateId = blockStateId;
-        acknowledgePlayerDiggingPacket.status = status;
-        acknowledgePlayerDiggingPacket.successful = success;
-
-        player.getPlayerConnection().sendPacket(acknowledgePlayerDiggingPacket);
     }
-
 }

src/main/java/net/minestom/server/network/netty/NettyServer.java

@@ -13,9 +13,6 @@ import io.netty.channel.nio.NioEventLoopGroup;
 import io.netty.channel.socket.ServerSocketChannel;
 import io.netty.channel.socket.SocketChannel;
 import io.netty.channel.socket.nio.NioServerSocketChannel;
-import io.netty.incubator.channel.uring.IOUring;
-import io.netty.incubator.channel.uring.IOUringEventLoopGroup;
-import io.netty.incubator.channel.uring.IOUringServerSocketChannel;
 import net.minestom.server.MinecraftServer;
 import net.minestom.server.network.PacketProcessor;
 import net.minestom.server.network.netty.channel.ClientChannel;
@@ -82,14 +79,7 @@ public final class NettyServer {
 
         // Find boss/worker event group
         {
-            if (IOUring.isAvailable()) {
+            if (Epoll.isAvailable()) {
-                boss = new IOUringEventLoopGroup(2);
-                worker = new IOUringEventLoopGroup(workerThreadCount);
-
-                channel = IOUringServerSocketChannel.class;
-
-                LOGGER.info("Using io_uring");
-            } else if (Epoll.isAvailable()) {
                 boss = new EpollEventLoopGroup(2);
                 worker = new EpollEventLoopGroup(workerThreadCount);
 

src/main/java/net/minestom/server/network/netty/codec/PacketCompressor.java

@@ -16,10 +16,8 @@
 
 package net.minestom.server.network.netty.codec;
 
-import com.velocitypowered.natives.compression.VelocityCompressor;
-import com.velocitypowered.natives.util.MoreByteBufUtils;
-import com.velocitypowered.natives.util.Natives;
 import io.netty.buffer.ByteBuf;
+import io.netty.buffer.Unpooled;
 import io.netty.channel.ChannelHandlerContext;
 import io.netty.handler.codec.ByteToMessageCodec;
 import io.netty.handler.codec.DecoderException;
@@ -27,6 +25,8 @@ import net.minestom.server.utils.PacketUtils;
 import net.minestom.server.utils.Utils;
 
 import java.util.List;
+import java.util.zip.Deflater;
+import java.util.zip.Inflater;
 
 public class PacketCompressor extends ByteToMessageCodec<ByteBuf> {
 
@@ -34,7 +34,8 @@ public class PacketCompressor extends ByteToMessageCodec<ByteBuf> {
 
     private final int threshold;
 
-    private final VelocityCompressor compressor = Natives.compress.get().create(4);
+    private final Deflater deflater = new Deflater();
+    private final Inflater inflater = new Inflater();
 
     public PacketCompressor(int threshold) {
         this.threshold = threshold;
@@ -42,7 +43,7 @@ public class PacketCompressor extends ByteToMessageCodec<ByteBuf> {
 
     @Override
     protected void encode(ChannelHandlerContext ctx, ByteBuf from, ByteBuf to) {
-        PacketUtils.compressBuffer(compressor, from, to);
+        PacketUtils.compressBuffer(deflater, from, to);
     }
 
     @Override
@@ -61,19 +62,17 @@ public class PacketCompressor extends ByteToMessageCodec<ByteBuf> {
                     throw new DecoderException("Badly compressed packet - size of " + claimedUncompressedSize + " is larger than protocol maximum of " + MAX_SIZE);
                 }
 
+                // TODO optimize to do not initialize arrays each time
 
-                ByteBuf compatibleIn = MoreByteBufUtils.ensureCompatible(ctx.alloc(), compressor, in);
+                byte[] input = new byte[in.readableBytes()];
-                ByteBuf uncompressed = MoreByteBufUtils.preferredBuffer(ctx.alloc(), compressor, claimedUncompressedSize);
+                in.readBytes(input);
-                try {
+
-                    compressor.inflate(compatibleIn, uncompressed, claimedUncompressedSize);
+                inflater.setInput(input);
-                    out.add(uncompressed);
+                byte[] output = new byte[claimedUncompressedSize];
-                    in.clear();
+                inflater.inflate(output);
-                } catch (Exception e) {
+                inflater.reset();
-                    uncompressed.release();
+
-                    throw e;
+                out.add(Unpooled.wrappedBuffer(output));
-                } finally {
-                    compatibleIn.release();
-                }
             }
         }
     }

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

@@ -10,12 +10,22 @@ import org.jetbrains.annotations.NotNull;
 
 public class AcknowledgePlayerDiggingPacket implements ServerPacket {
 
-    public BlockPosition blockPosition = new BlockPosition(0,0,0);
+    public BlockPosition blockPosition;
     public int blockStateId;
-    public ClientPlayerDiggingPacket.Status status = ClientPlayerDiggingPacket.Status.STARTED_DIGGING;
+    public ClientPlayerDiggingPacket.Status status;
     public boolean successful;
 
-    public AcknowledgePlayerDiggingPacket() {}
+    public AcknowledgePlayerDiggingPacket(@NotNull BlockPosition blockPosition, int blockStateId,
+                                          @NotNull ClientPlayerDiggingPacket.Status status, boolean success) {
+        this.blockPosition = blockPosition;
+        this.blockStateId = blockStateId;
+        this.status = status;
+        this.successful = success;
+    }
+
+    public AcknowledgePlayerDiggingPacket() {
+        this(new BlockPosition(0, 0, 0), 0, ClientPlayerDiggingPacket.Status.STARTED_DIGGING, false);
+    }
 
     @Override
     public void write(@NotNull BinaryWriter writer) {

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

@@ -9,13 +9,14 @@ import org.jetbrains.annotations.NotNull;
 
 public class ActionBarPacket implements ServerPacket {
 
-    public Component actionBarText = Component.empty();
+    public Component actionBarText;
 
-    public ActionBarPacket() {
+    public ActionBarPacket(@NotNull Component actionBarText) {
+        this.actionBarText = actionBarText;
     }
 
-    public ActionBarPacket(Component actionBarText) {
+    public ActionBarPacket() {
-        this.actionBarText = actionBarText;
+        this(Component.empty());
     }
 
     @Override

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

@@ -1,17 +1,30 @@
 package net.minestom.server.network.packet.server.play;
 
+import net.minestom.server.entity.Entity;
 import net.minestom.server.network.packet.server.ServerPacket;
 import net.minestom.server.network.packet.server.ServerPacketIdentifier;
 import net.minestom.server.utils.binary.BinaryReader;
 import net.minestom.server.utils.binary.BinaryWriter;
 import org.jetbrains.annotations.NotNull;
+import org.jetbrains.annotations.Nullable;
 
 public class AttachEntityPacket implements ServerPacket {
 
     public int attachedEntityId;
     public int holdingEntityId; // Or -1 to detach
 
-    public AttachEntityPacket() {}
+    public AttachEntityPacket(int attachedEntityId, int holdingEntityId) {
+        this.attachedEntityId = attachedEntityId;
+        this.holdingEntityId = holdingEntityId;
+    }
+
+    public AttachEntityPacket(@NotNull Entity attachedEntity, @Nullable Entity holdingEntity) {
+        this(attachedEntity.getEntityId(), holdingEntity != null ? holdingEntity.getEntityId() : -1);
+    }
+
+    public AttachEntityPacket() {
+        this(0, 0);
+    }
 
     @Override
     public void write(@NotNull BinaryWriter writer) {

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

@@ -12,8 +12,13 @@ public class BlockChangePacket implements ServerPacket {
     public BlockPosition blockPosition;
     public int blockStateId;
 
+    public BlockChangePacket(BlockPosition blockPosition, int blockStateId) {
+        this.blockPosition = blockPosition;
+        this.blockStateId = blockStateId;
+    }
+
     public BlockChangePacket() {
-        blockPosition = new BlockPosition(0,0,0);
+        this(new BlockPosition(0, 0, 0), 0);
     }
 
     @Override

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

@@ -1,5 +1,6 @@
 package net.minestom.server.network.packet.server.play;
 
+import net.minestom.server.entity.Entity;
 import net.minestom.server.network.packet.server.ServerPacket;
 import net.minestom.server.network.packet.server.ServerPacketIdentifier;
 import net.minestom.server.utils.binary.BinaryReader;
@@ -10,7 +11,17 @@ public class CameraPacket implements ServerPacket {
 
     public int cameraId;
 
-    public CameraPacket() {}
+    public CameraPacket(int cameraId) {
+        this.cameraId = cameraId;
+    }
+
+    public CameraPacket(@NotNull Entity camera) {
+        this(camera.getEntityId());
+    }
+
+    public CameraPacket() {
+        this(0);
+    }
 
     @Override
     public void write(@NotNull BinaryWriter writer) {

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

@@ -26,18 +26,16 @@ public class ChatMessagePacket implements ComponentHoldingServerPacket {
     public ChatPosition position;
     public UUID uuid;
 
-    public ChatMessagePacket() {
-        this.message = Component.empty();
-        this.position = ChatPosition.SYSTEM_MESSAGE;
-        this.uuid = NULL_UUID;
-    }
-
     public ChatMessagePacket(@NotNull Component message, @NotNull ChatPosition position, @Nullable UUID uuid) {
         this.message = message;
         this.position = position;
         this.uuid = Objects.requireNonNullElse(uuid, NULL_UUID);
     }
 
+    public ChatMessagePacket() {
+        this(Component.empty(), ChatPosition.SYSTEM_MESSAGE, NULL_UUID);
+    }
+
     @Override
     public void write(@NotNull BinaryWriter writer) {
         writer.writeComponent(message);

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

@@ -13,7 +13,8 @@ public class ExplosionPacket implements ServerPacket {
     public byte[] records = new byte[0];
     public float playerMotionX, playerMotionY, playerMotionZ;
 
-    public ExplosionPacket() {}
+    public ExplosionPacket() {
+    }
 
     @Override
     public void write(@NotNull BinaryWriter writer) {
@@ -21,7 +22,7 @@ public class ExplosionPacket implements ServerPacket {
         writer.writeFloat(y);
         writer.writeFloat(z);
         writer.writeFloat(radius);
-        writer.writeInt(records.length/3); // each record is 3 bytes long
+        writer.writeVarInt(records.length / 3); // each record is 3 bytes long
         for (byte record : records)
             writer.writeByte(record);
         writer.writeFloat(playerMotionX);

src/main/java/net/minestom/server/scoreboard/Team.java

@@ -1,6 +1,5 @@
 package net.minestom.server.scoreboard;
 
-import com.google.common.collect.MapMaker;
 import net.kyori.adventure.identity.Identity;
 import net.kyori.adventure.pointer.Pointers;
 import net.kyori.adventure.text.Component;
@@ -22,6 +21,7 @@ import org.jetbrains.annotations.NotNull;
 import java.util.Collection;
 import java.util.Collections;
 import java.util.Set;
+import java.util.concurrent.ConcurrentHashMap;
 import java.util.concurrent.CopyOnWriteArraySet;
 
 /**
@@ -72,7 +72,7 @@ public class Team implements PacketGroupingAudience {
      */
     private Component suffix;
 
-    private final Set<Player> playerMembers = Collections.newSetFromMap(new MapMaker().weakKeys().makeMap());
+    private final Set<Player> playerMembers = ConcurrentHashMap.newKeySet();
     private boolean isPlayerMembersUpToDate;
 
     // Adventure

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

@@ -6,7 +6,11 @@ import org.jetbrains.annotations.NotNull;
 import org.jetbrains.annotations.Nullable;
 import org.jglrxavpok.hephaistos.nbt.NBT;
 import org.jglrxavpok.hephaistos.nbt.NBTCompound;
+import org.jglrxavpok.hephaistos.nbt.NBTException;
+import org.jglrxavpok.hephaistos.nbt.SNBTParser;
 
+import java.io.StringReader;
+import java.util.Objects;
 import java.util.function.BiConsumer;
 import java.util.function.Function;
 import java.util.function.Supplier;
@@ -21,29 +25,68 @@ import java.util.function.Supplier;
 @ApiStatus.NonExtendable
 public class Tag<T> {
 
+    /**
+     * Handles the snbt of the tag holder.
+     * <p>
+     * Writing will override all tags. Proceed with caution.
+     */
+    @ApiStatus.Experimental
+    public static final Tag<String> SNBT = new Tag<>(null, NBTCompound::toSNBT, (original, snbt) -> {
+        try {
+            final var updated = new SNBTParser(new StringReader(snbt)).parse();
+            if (!(updated instanceof NBTCompound))
+                throw new IllegalArgumentException("'" + snbt + "' is not a compound!");
+            NBTCompound updatedCompound = (NBTCompound) updated;
+            original.clear();
+            updatedCompound.getKeys().forEach(s ->
+                    original.set(s, Objects.requireNonNull(updatedCompound.get(s))));
+        } catch (NBTException e) {
+            e.printStackTrace();
+        }
+    }, null);
+
+    /**
+     * Handles the complete tag holder compound.
+     * <p>
+     * Writing will override all tags. Proceed with caution.
+     */
+    @ApiStatus.Experimental
+    public static final Tag<NBTCompound> NBT = new Tag<>(null, NBTCompound::deepClone, (original, updated) -> {
+        original.clear();
+        updated.getKeys().forEach(s -> original.set(s, Objects.requireNonNull(updated.get(s))));
+    }, null);
+
     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,
+    protected Tag(@Nullable String key,
                   @NotNull Function<NBTCompound, T> readFunction,
-                  @NotNull BiConsumer<NBTCompound, T> writeConsumer,
+                  @Nullable BiConsumer<NBTCompound, T> writeConsumer,
                   @Nullable Supplier<T> defaultValue) {
         this.key = key;
         this.readFunction = readFunction;
-        this.writeConsumer = writeConsumer;
+        this.writeConsumer = Objects.requireNonNullElse(writeConsumer, (compound, t) -> {
+        });
         this.defaultValue = defaultValue;
     }
 
-    protected Tag(@NotNull String key,
+    protected Tag(@Nullable String key,
                   @NotNull Function<NBTCompound, T> readFunction,
-                  @NotNull BiConsumer<NBTCompound, T> writeConsumer) {
+                  @Nullable BiConsumer<NBTCompound, T> writeConsumer) {
         this(key, readFunction, writeConsumer, null);
     }
 
-    public @NotNull String getKey() {
+    /**
+     * Returns the key used to navigate inside the holder nbt.
+     * <p>
+     * Can be null if unused (e.g. {@link #View(TagSerializer)}, {@link #SNBT} and {@link #NBT}).
+     *
+     * @return the tag key
+     */
+    public @Nullable String getKey() {
         return key;
     }
 
@@ -60,7 +103,7 @@ public class Tag<T> {
     @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,
+        return new Tag<>(key,
                 // Read
                 nbtCompound -> {
                     final var old = readFunction.apply(nbtCompound);
@@ -85,22 +128,26 @@ public class Tag<T> {
     }
 
     public @Nullable T read(@NotNull NBTCompound nbtCompound) {
-        if (nbtCompound.containsKey(key)) {
+        T result = readFunction.apply(nbtCompound);
-            return readFunction.apply(nbtCompound);
+        if (result == null) {
-        } else {
             final var supplier = defaultValue;
-            return supplier != null ? supplier.get() : null;
+            result = supplier != null ? supplier.get() : null;
         }
+        return result;
     }
 
     public void write(@NotNull NBTCompound nbtCompound, @Nullable T value) {
-        if (value != null) {
+        if (key == null || value != null) {
             this.writeConsumer.accept(nbtCompound, value);
         } else {
             nbtCompound.removeTag(key);
         }
     }
 
+    public void writeUnsafe(@NotNull NBTCompound nbtCompound, @Nullable Object value) {
+        write(nbtCompound, (T) value);
+    }
+
     public static @NotNull Tag<Byte> Byte(@NotNull String key) {
         return new Tag<>(key,
                 nbtCompound -> nbtCompound.getByte(key),
@@ -149,17 +196,15 @@ public class Tag<T> {
                 (nbtCompound, value) -> nbtCompound.setString(key, value));
     }
 
-    public static @NotNull Tag<NBT> NBT(@NotNull String key) {
+    public static <T extends NBT> @NotNull Tag<T> NBT(@NotNull String key) {
         return new Tag<>(key,
                 nbt -> {
-                    var currentNBT = nbt.get(key);
+                    final var currentNBT = nbt.get(key);
-
                     // Avoid a NPE when cloning a null variable.
                     if (currentNBT == null) {
                         return null;
                     }
-
+                    return (T) currentNBT.deepClone();
-                    return currentNBT.deepClone();
                 },
                 ((nbt, value) -> nbt.set(key, value.deepClone())));
     }
@@ -176,7 +221,15 @@ public class Tag<T> {
                 (nbtCompound, value) -> nbtCompound.setLongArray(key, value));
     }
 
-    public static <T> @NotNull Tag<T> Custom(@NotNull String key, @NotNull TagSerializer<T> serializer) {
+    /**
+     * Create a wrapper around a compound.
+     *
+     * @param key        the tag key
+     * @param serializer the tag serializer
+     * @param <T>        the tag type
+     * @return the created tag
+     */
+    public static <T> @NotNull Tag<T> Structure(@NotNull String key, @NotNull TagSerializer<T> serializer) {
         return new Tag<>(key,
                 nbtCompound -> {
                     final var compound = nbtCompound.getCompound(key);
@@ -194,4 +247,18 @@ public class Tag<T> {
                     serializer.write(TagWritable.fromCompound(compound), value);
                 });
     }
+
+    public static <T> @NotNull Tag<T> View(@NotNull TagSerializer<T> serializer) {
+        return new Tag<>(null,
+                nbtCompound -> serializer.read(TagReadable.fromCompound(nbtCompound)),
+                (nbtCompound, value) -> serializer.write(TagWritable.fromCompound(nbtCompound), value));
+    }
+
+    /**
+     * @deprecated use {@link #Structure(String, TagSerializer)} instead
+     */
+    @Deprecated
+    public static <T> @NotNull Tag<T> Custom(@NotNull String key, @NotNull TagSerializer<T> serializer) {
+        return Structure(key, serializer);
+    }
 }

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

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

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

@@ -24,7 +24,9 @@ public interface TagReadable {
      * @param tag the tag to check
      * @return true if the tag is present, false otherwise
      */
-    boolean hasTag(@NotNull Tag<?> tag);
+    default boolean hasTag(@NotNull Tag<?> tag) {
+        return getTag(tag) != null;
+    }
 
     /**
      * Converts an nbt compound to a tag reader.
@@ -38,11 +40,6 @@ public interface TagReadable {
             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

@@ -4,7 +4,7 @@ import org.jetbrains.annotations.NotNull;
 import org.jetbrains.annotations.Nullable;
 
 /**
- * Interface used to create custom types compatible with {@link Tag#Custom(String, TagSerializer)}.
+ * Interface used to create custom {@link Tag tags}.
  *
  * @param <T> the type to serialize
  */
@@ -14,7 +14,7 @@ public interface TagSerializer<T> {
      * Reads the custom tag from a {@link TagReadable}.
      *
      * @param reader the reader
-     * @return the deserialized value
+     * @return the deserialized value, null if invalid
      */
     @Nullable T read(@NotNull TagReadable reader);
 
@@ -22,7 +22,7 @@ public interface TagSerializer<T> {
      * Writes the custom tag to a {@link TagWritable}.
      *
      * @param writer the writer
-     * @param value  the value to serialize
+     * @param value  the value to serialize, null to remove
      */
-    void write(@NotNull TagWritable writer, @NotNull T value);
+    void write(@NotNull TagWritable writer, @Nullable T value);
 }

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

@@ -18,6 +18,10 @@ public interface TagWritable {
      */
     <T> void setTag(@NotNull Tag<T> tag, @Nullable T value);
 
+    default void removeTag(@NotNull Tag<?> tag) {
+        setTag(tag, null);
+    }
+
     /**
      * Converts an nbt compound to a tag writer.
      *

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

@@ -47,10 +47,6 @@ public final class MathUtils {
         return Direction.HORIZONTAL[directionIndex];
     }
 
-    public static float clampFloat(float t, float a, float b) {
-        return Math.max(a, Math.min(t, b));
-    }
-
     public static boolean isBetween(byte number, byte min, byte max) {
         return number >= min && number <= max;
     }
@@ -84,11 +80,15 @@ public final class MathUtils {
     }
 
     public static int clamp(int value, int min, int max) {
-        if (value < min) {
+        return Math.min(Math.max(value, min), max);
-            return min;
-        } else {
-            return Math.min(value, max);
     }
+
+    public static float clamp(float value, float min, float max) {
+        return Math.min(Math.max(value, min), max);
+    }
+
+    public static double clamp(double value, double min, double max) {
+        return Math.min(Math.max(value, min), max);
     }
 
     public static double mod(final double a, final double b) {

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

@@ -1,12 +1,9 @@
 package net.minestom.server.utils;
 
-import com.velocitypowered.natives.compression.VelocityCompressor;
-import com.velocitypowered.natives.util.Natives;
 import io.netty.buffer.ByteBuf;
 import net.kyori.adventure.audience.Audience;
 import net.kyori.adventure.audience.ForwardingAudience;
 import net.minestom.server.MinecraftServer;
-import net.minestom.server.adventure.AdventureSerializer;
 import net.minestom.server.adventure.MinestomAdventure;
 import net.minestom.server.adventure.audience.PacketGroupingAudience;
 import net.minestom.server.entity.Player;
@@ -21,8 +18,9 @@ import net.minestom.server.utils.callback.validator.PlayerValidator;
 import org.jetbrains.annotations.NotNull;
 import org.jetbrains.annotations.Nullable;
 
+import java.nio.ByteBuffer;
 import java.util.Collection;
-import java.util.zip.DataFormatException;
+import java.util.zip.Deflater;
 
 /**
  * Utils class for packets. Including writing a {@link ServerPacket} into a {@link ByteBuf}
@@ -31,7 +29,7 @@ import java.util.zip.DataFormatException;
 public final class PacketUtils {
 
     private static final PacketListenerManager PACKET_LISTENER_MANAGER = MinecraftServer.getPacketListenerManager();
-    private static final ThreadLocal<VelocityCompressor> COMPRESSOR = ThreadLocal.withInitial(() -> Natives.compress.get().create(4));
+    private static final ThreadLocal<Deflater> COMPRESSOR = ThreadLocal.withInitial(Deflater::new);
 
     private PacketUtils() {
     }
@@ -189,29 +187,37 @@ public final class PacketUtils {
      * <p>
      * {@code packetBuffer} needs to be the packet content without any header (if you want to use it to write a Minecraft packet).
      *
-     * @param compressor        the deflater for zlib compression
+     * @param deflater          the deflater for zlib compression
      * @param packetBuffer      the buffer containing all the packet fields
      * @param compressionTarget the buffer which will receive the compressed version of {@code packetBuffer}
      */
-    public static void compressBuffer(@NotNull VelocityCompressor compressor, @NotNull ByteBuf packetBuffer, @NotNull ByteBuf compressionTarget) {
+    public static void compressBuffer(@NotNull Deflater deflater, @NotNull ByteBuf packetBuffer, @NotNull ByteBuf compressionTarget) {
         final int packetLength = packetBuffer.readableBytes();
         final boolean compression = packetLength > MinecraftServer.getCompressionThreshold();
         Utils.writeVarInt(compressionTarget, compression ? packetLength : 0);
         if (compression) {
-            compress(compressor, packetBuffer, compressionTarget);
+            compress(deflater, packetBuffer, compressionTarget);
         } else {
             compressionTarget.writeBytes(packetBuffer);
         }
     }
 
-    private static void compress(@NotNull VelocityCompressor compressor, @NotNull ByteBuf uncompressed, @NotNull ByteBuf compressed) {
+    private static void compress(@NotNull Deflater deflater, @NotNull ByteBuf uncompressed, @NotNull ByteBuf compressed) {
-        try {
+        deflater.setInput(uncompressed.nioBuffer());
-            compressor.deflate(uncompressed, compressed);
+        deflater.finish();
-        } catch (DataFormatException e) {
+
-            e.printStackTrace();
+        while (!deflater.finished()) {
+            ByteBuffer nioBuffer = compressed.nioBuffer(compressed.writerIndex(), compressed.writableBytes());
+            compressed.writerIndex(deflater.deflate(nioBuffer) + compressed.writerIndex());
+
+            if (compressed.writableBytes() == 0) {
+                compressed.ensureWritable(8192);
             }
         }
 
+        deflater.reset();
+    }
+
     public static void writeFramedPacket(@NotNull ByteBuf buffer,
                                          @NotNull ServerPacket serverPacket) {
         final int compressionThreshold = MinecraftServer.getCompressionThreshold();

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

@@ -1,6 +1,5 @@
 package net.minestom.server.utils;
 
-import com.google.common.primitives.Doubles;
 import net.minestom.server.MinecraftServer;
 import net.minestom.server.utils.clone.PublicCloneable;
 import org.jetbrains.annotations.NotNull;
@@ -167,7 +166,7 @@ public class Vector implements PublicCloneable<Vector> {
      * @return angle in radians
      */
     public float angle(@NotNull Vector other) {
-        double dot = Doubles.constrainToRange(dot(other) / (length() * other.length()), -1.0, 1.0);
+        double dot = MathUtils.clamp(dot(other) / (length() * other.length()), -1.0, 1.0);
 
         return (float) Math.acos(dot);
     }

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

@@ -1,8 +1,8 @@
 package net.minestom.server.utils.cache;
 
-import com.google.common.cache.Cache;
+import com.github.benmanes.caffeine.cache.Cache;
-import com.google.common.cache.CacheBuilder;
+import com.github.benmanes.caffeine.cache.Caffeine;
-import com.google.common.cache.RemovalListener;
+import com.github.benmanes.caffeine.cache.RemovalListener;
 import org.jetbrains.annotations.NotNull;
 import org.jetbrains.annotations.Nullable;
 
@@ -24,7 +24,7 @@ public class TemporaryCache<T> {
      * @param duration the time before considering an object unused
      */
     public TemporaryCache(long duration, TimeUnit timeUnit, RemovalListener<UUID, T> removalListener) {
-        this.cache = CacheBuilder.newBuilder()
+        this.cache = Caffeine.newBuilder()
                 .expireAfterWrite(duration, timeUnit)
                 .removalListener(removalListener)
                 .build();

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

@@ -6,8 +6,10 @@ import java.util.concurrent.TimeUnit;
 
 public class TemporaryPacketCache extends TemporaryCache<TimedBuffer> {
     public TemporaryPacketCache(long duration, TimeUnit timeUnit) {
-        super(duration, timeUnit, notification -> {
+        super(duration, timeUnit, (key, value, cause) -> {
-            final ByteBuf buffer = notification.getValue().getBuffer();
+            if (value == null)
+                return;
+            final ByteBuf buffer = value.getBuffer();
             synchronized (buffer) {
                 buffer.release();
             }

src/main/java/net/minestom/server/utils/location/RelativeBlockPosition.java

@@ -28,4 +28,17 @@ public class RelativeBlockPosition extends RelativeLocation<BlockPosition> {
 
         return new BlockPosition(x, y, z);
     }
+
+    @Override
+    public BlockPosition fromView(@Nullable Position position) {
+        if (!relativeX && !relativeY && !relativeZ) {
+            return location.clone();
+        }
+        final Position entityPosition = position != null ? position : new Position();
+
+        final int x = location.getX() + (relativeX ? (int) entityPosition.getYaw() : 0);
+        final int z = location.getZ() + (relativeZ ? (int) entityPosition.getPitch() : 0);
+
+        return new BlockPosition(x, 0, z);
+    }
 }

src/main/java/net/minestom/server/utils/location/RelativeLocation.java

@@ -2,6 +2,7 @@ package net.minestom.server.utils.location;
 
 import net.minestom.server.entity.Entity;
 import net.minestom.server.utils.Position;
+import org.jetbrains.annotations.ApiStatus;
 import org.jetbrains.annotations.NotNull;
 import org.jetbrains.annotations.Nullable;
 
@@ -22,19 +23,6 @@ public abstract class RelativeLocation<T> {
         this.relativeZ = relativeZ;
     }
 
-    /**
-     * Gets the location based on the relative fields and {@code entity}.
-     *
-     * @param entity the entity to get the relative position from
-     * @return the location
-     */
-    public T from(@Nullable Entity entity) {
-
-        final Position entityPosition = entity != null ? entity.getPosition() : new Position();
-
-        return from(entityPosition);
-    }
-
     /**
      * Gets the location based on the relative fields and {@code position}.
      *
@@ -43,6 +31,26 @@ public abstract class RelativeLocation<T> {
      */
     public abstract T from(@Nullable Position position);
 
+    @ApiStatus.Experimental
+    public abstract T fromView(@Nullable Position position);
+
+    /**
+     * Gets the location based on the relative fields and {@code entity}.
+     *
+     * @param entity the entity to get the relative position from
+     * @return the location
+     */
+    public T from(@Nullable Entity entity) {
+        final Position entityPosition = entity != null ? entity.getPosition() : new Position();
+        return from(entityPosition);
+    }
+
+    @ApiStatus.Experimental
+    public T fromView(@Nullable Entity entity) {
+        final Position entityPosition = entity != null ? entity.getPosition() : new Position();
+        return fromView(entityPosition);
+    }
+
     /**
      * Gets if the 'x' field is relative.
      *

src/main/java/net/minestom/server/utils/location/RelativeVec.java

@@ -28,4 +28,17 @@ public class RelativeVec extends RelativeLocation<Vector> {
 
         return new Vector(x, y, z);
     }
+
+    @Override
+    public Vector fromView(@Nullable Position position) {
+        if (!relativeX && !relativeY && !relativeZ) {
+            return location.clone();
+        }
+        final Position entityPosition = position != null ? position : new Position();
+
+        final double x = location.getX() + (relativeX ? entityPosition.getYaw() : 0);
+        final double z = location.getZ() + (relativeZ ? entityPosition.getPitch() : 0);
+
+        return new Vector(x, 0, z);
+    }
 }

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

@@ -1,7 +1,7 @@
 package net.minestom.server.utils.mojang;
 
-import com.google.common.cache.Cache;
+import com.github.benmanes.caffeine.cache.Cache;
-import com.google.common.cache.CacheBuilder;
+import com.github.benmanes.caffeine.cache.Caffeine;
 import com.google.gson.JsonObject;
 import com.google.gson.JsonParser;
 import net.minestom.server.MinecraftServer;
@@ -17,12 +17,12 @@ import java.util.concurrent.TimeUnit;
  */
 public final class MojangUtils {
 
-    private static final Cache<String, JsonObject> UUID_CACHE = CacheBuilder.newBuilder()
+    private static final Cache<String, JsonObject> UUID_CACHE = Caffeine.newBuilder()
             .expireAfterWrite(30, TimeUnit.SECONDS)
             .softValues()
             .build();
 
-    private static final Cache<String, JsonObject> USERNAME_CACHE = CacheBuilder.newBuilder()
+    private static final Cache<String, JsonObject> USERNAME_CACHE = Caffeine.newBuilder()
             .expireAfterWrite(30, TimeUnit.SECONDS)
             .softValues()
             .build();

src/test/java/demo/PlayerInit.java

@@ -55,16 +55,12 @@ public class PlayerInit {
             .addListener(EntityAttackEvent.class, event -> {
                 final Entity source = event.getEntity();
                 final Entity entity = event.getTarget();
+
+                entity.takeKnockback(0.4f, Math.sin(source.getPosition().getYaw() * 0.017453292), -Math.cos(source.getPosition().getYaw() * 0.017453292));
+
                 if (entity instanceof Player) {
                     Player target = (Player) entity;
-                    Vector velocity = source.getPosition().clone().getDirection().multiply(4);
-                    velocity.setY(3.5f);
-                    target.setVelocity(velocity);
                     target.damage(DamageType.fromEntity(source), 5);
-                } else {
-                    Vector velocity = source.getPosition().clone().getDirection().multiply(3);
-                    velocity.setY(3f);
-                    entity.setVelocity(velocity);
                 }
 
                 if (source instanceof Player) {