Merge branch 'master' of https://github.com/Minestom/Minestom

 Conflicts:

	src/main/java/net/minestom/server/benchmark/BenchmarkManager.java

.github/README.md

@@ -5,10 +5,9 @@
 [![standard-readme compliant](https://img.shields.io/badge/readme%20style-standard-brightgreen.svg?style=flat-square)](https://github.com/RichardLitt/standard-readme)  
 [![discord-banner](https://discordapp.com/api/guilds/706185253441634317/widget.png?style=banner2)](https://discord.gg/pkFRvqB)
 
-Minestom is an alternative to the popular Minecraft server API called Bukkit.
+Minestom is a complete rewrite of Minecraft server software, open-source and without any code from Mojang.
 
-
+The main difference compared to it is that our implementation of the Notchian server does not contain any features by default!
-The main difference is that our implementation of the Notchian server does not contain any features by default!
 However, we have a complete API which allows you to make anything possible with current spigot plugins.
 
 This is a developer API not meant to be used by the end-users. Replacing Spigot/Paper with this will **not** work since we do not implement the Bukkit API.

build.gradle

@@ -143,7 +143,7 @@ dependencies {
     api "org.spongepowered:mixin:${mixinVersion}"
 
     // Path finding
-    api 'com.github.MadMartian:hydrazine-path-finding:1.4.2'
+    api 'com.github.MadMartian:hydrazine-path-finding:1.5.0'
 
     api "org.jetbrains.kotlin:kotlin-stdlib-jdk8"
 

src/autogenerated/java/net/minestom/server/entity/EntityType.java

@@ -242,7 +242,7 @@ public enum EntityType {
     }
 
     public static EntityType fromId(int id) {
-        if(id >= 0 && id < values().length) {
+        if (id >= 0 && id < values().length) {
             return values()[id];
         }
         return PIG;

src/autogenerated/java/net/minestom/server/fluids/Fluid.java

@@ -36,7 +36,7 @@ public enum Fluid {
     }
 
     public static Fluid fromId(int id) {
-        if(id >= 0 && id < values().length) {
+        if (id >= 0 && id < values().length) {
             return values()[id];
         }
         return EMPTY;

src/autogenerated/java/net/minestom/server/item/Enchantment.java

@@ -102,7 +102,7 @@ public enum Enchantment {
     }
 
     public static Enchantment fromId(int id) {
-        if(id >= 0 && id < values().length) {
+        if (id >= 0 && id < values().length) {
             return values()[id];
         }
         return null;

src/autogenerated/java/net/minestom/server/particle/Particle.java

@@ -170,7 +170,7 @@ public enum Particle {
     }
 
     public static Particle fromId(int id) {
-        if(id >= 0 && id < values().length) {
+        if (id >= 0 && id < values().length) {
             return values()[id];
         }
         return null;

src/autogenerated/java/net/minestom/server/potion/PotionEffect.java

@@ -82,7 +82,7 @@ public enum PotionEffect {
     }
 
     public int getId() {
-        return ordinal();
+        return ordinal() + 1;
     }
 
     public String getNamespaceID() {
@@ -90,8 +90,8 @@ public enum PotionEffect {
     }
 
     public static PotionEffect fromId(int id) {
-        if(id >= 0 && id < values().length) {
+        if (id >= 0 && id < values().length + 1) {
-            return values()[id];
+            return values()[id - 1];
         }
         return null;
     }

src/autogenerated/java/net/minestom/server/potion/PotionType.java

@@ -112,7 +112,7 @@ public enum PotionType {
     }
 
     public static PotionType fromId(int id) {
-        if(id >= 0 && id < values().length) {
+        if (id >= 0 && id < values().length) {
             return values()[id];
         }
         return EMPTY;

src/autogenerated/java/net/minestom/server/sound/Sound.java

@@ -2010,7 +2010,7 @@ public enum Sound {
     }
 
     public static Sound fromId(int id) {
-        if(id >= 0 && id < values().length) {
+        if (id >= 0 && id < values().length) {
             return values()[id];
         }
         return null;

src/autogenerated/java/net/minestom/server/stat/StatisticType.java

@@ -174,7 +174,7 @@ public enum StatisticType {
     }
 
     public static StatisticType fromId(int id) {
-        if(id >= 0 && id < values().length) {
+        if (id >= 0 && id < values().length) {
             return values()[id];
         }
         return null;

src/generators/java/net/minestom/codegen/BasicEnumGenerator.java

@@ -20,13 +20,23 @@ public abstract class BasicEnumGenerator extends MinestomEnumGenerator<BasicEnum
     private final boolean linear;
     private NamespaceID defaultEntry;
 
-    protected BasicEnumGenerator(File targetFolder) throws IOException {
+    /**
-        this(targetFolder, true);
+     * True if the enum is linear and start by 1 instead of 0
+     */
+    private boolean incrementOrdinal;
+
+    protected BasicEnumGenerator(File targetFolder, boolean linear, boolean incrementOrdinal) throws IOException {
+        this.linear = linear;
+        this.incrementOrdinal = incrementOrdinal;
+        generateTo(targetFolder);
     }
 
     protected BasicEnumGenerator(File targetFolder, boolean linear) throws IOException {
-        this.linear = linear;
+        this(targetFolder, linear, false);
-        generateTo(targetFolder);
+    }
+
+    protected BasicEnumGenerator(File targetFolder) throws IOException {
+        this(targetFolder, true);
     }
 
     @Override
@@ -59,17 +69,19 @@ public abstract class BasicEnumGenerator extends MinestomEnumGenerator<BasicEnum
         ParameterSpec idParam = ParameterSpec.builder(TypeName.INT, "id").build();
         ParameterSpec[] signature = new ParameterSpec[]{idParam};
         if (linear) {
+            final String ordinalIncrementCondition = incrementOrdinal ? " + 1" : "";
+            final String ordinalIncrementIndex = incrementOrdinal ? " - 1" : "";
             generator.addStaticMethod("fromId", signature, className, code -> {
-                        code.beginControlFlow("if($N >= 0 && $N < values().length)", idParam, idParam)
+                        code.beginControlFlow("if ($N >= 0 && $N < values().length" + ordinalIncrementCondition + ")", idParam, idParam)
-                                .addStatement("return values()[$N]", idParam)
+                                .addStatement("return values()[$N" + ordinalIncrementIndex + "]", idParam)
                                 .endControlFlow()
                                 .addStatement("return " + (defaultEntry == null ? "null" : identifier(defaultEntry)));
                     }
             );
         } else {
             generator.addStaticMethod("fromId", signature, className, code -> {
-                        code.beginControlFlow("for($T o : values())")
+                        code.beginControlFlow("for ($T o : values())")
-                                .beginControlFlow("if(o.getId() == id)")
+                                .beginControlFlow("if (o.getId() == id)")
                                 .addStatement("return o")
                                 .endControlFlow()
                                 .endControlFlow()
@@ -94,7 +106,7 @@ public abstract class BasicEnumGenerator extends MinestomEnumGenerator<BasicEnum
         ClassName registriesClass = ClassName.get(Registries.class);
         if (linear) {
             generator.setParams(ParameterSpec.builder(ClassName.get(String.class), "namespaceID").build());
-            generator.addMethod("getId", new ParameterSpec[0], TypeName.INT, code -> code.addStatement("return ordinal()"));
+            generator.addMethod("getId", new ParameterSpec[0], TypeName.INT, code -> code.addStatement("return ordinal()" + (incrementOrdinal ? " + 1" : "")));
         } else {
             generator.setParams(ParameterSpec.builder(ClassName.get(String.class), "namespaceID").build(), ParameterSpec.builder(TypeName.INT, "id").build());
             generator.addMethod("getId", new ParameterSpec[0], TypeName.INT, code -> code.addStatement("return $N", "id"));

src/generators/java/net/minestom/codegen/potions/PotionEffectEnumGenerator.java

@@ -1,7 +1,6 @@
 package net.minestom.codegen.potions;
 
 import net.minestom.codegen.BasicEnumGenerator;
-import net.minestom.codegen.stats.StatsEnumGenerator;
 import net.minestom.server.registry.ResourceGatherer;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
@@ -42,7 +41,7 @@ public class PotionEffectEnumGenerator extends BasicEnumGenerator {
     }
 
     private PotionEffectEnumGenerator(File targetFolder) throws IOException {
-        super(targetFolder);
+        super(targetFolder, true, true);
     }
 
     @Override

src/main/java/net/minestom/server/benchmark/BenchmarkManager.java

@@ -99,11 +99,14 @@ public final class BenchmarkManager {
         return Runtime.getRuntime().totalMemory() - Runtime.getRuntime().freeMemory();
     }
 
+    @NotNull
     public Map<String, ThreadResult> getResultMap() {
         return Collections.unmodifiableMap(resultMap);
     }
 
+    @NotNull
     public String getCpuMonitoringMessage() {
+        Check.stateCondition(!enabled, "CPU monitoring is only possible when the benchmark manager is enabled.");
         StringBuilder benchmarkMessage = new StringBuilder();
         for (Map.Entry<String, ThreadResult> resultEntry : resultMap.entrySet()) {
             final String name = resultEntry.getKey();

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

@@ -580,11 +580,13 @@ public final class CommandManager {
         } else if (argument instanceof ArgumentDynamicWord) {
             DeclareCommandsPacket.Node argumentNode = simpleArgumentNode(nodes, argument, executable, true);
 
+            final SuggestionType suggestionType = ((ArgumentDynamicWord) argument).getSuggestionType();
+
             argumentNode.parser = "brigadier:string";
             argumentNode.properties = packetWriter -> {
                 packetWriter.writeVarInt(0); // Single word
             };
-            argumentNode.suggestionsType = "minecraft:ask_server";
+            argumentNode.suggestionsType = suggestionType.getIdentifier();
 
         } else if (argument instanceof ArgumentString) {
             DeclareCommandsPacket.Node argumentNode = simpleArgumentNode(nodes, argument, executable, false);

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

@@ -5,6 +5,7 @@ import net.minestom.server.command.builder.arguments.Argument;
 import net.minestom.server.command.builder.arguments.ArgumentDynamicStringArray;
 import net.minestom.server.command.builder.arguments.ArgumentDynamicWord;
 import net.minestom.server.command.builder.arguments.ArgumentType;
+import net.minestom.server.command.builder.arguments.minecraft.SuggestionType;
 import net.minestom.server.command.builder.condition.CommandCondition;
 import org.jetbrains.annotations.NotNull;
 import org.jetbrains.annotations.Nullable;
@@ -187,7 +188,8 @@ public class Command {
 
     /**
      * Allows for tab auto completion, this is called everytime the player press a key in the chat
-     * when in a dynamic argument ({@link ArgumentDynamicWord} and {@link ArgumentDynamicStringArray}).
+     * when in a dynamic argument ({@link ArgumentDynamicWord} (when {@link SuggestionType#ASK_SERVER} is used)
+     * and {@link ArgumentDynamicStringArray}).
      *
      * @param text the whole player's text
      * @return the array containing all the suggestion for the current arg (split " "), can be null

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

@@ -37,9 +37,9 @@ public class CommandDispatcher {
         this.commands.add(command);
     }
 
-    public void unregister(Command command) {
+    public void unregister(@NotNull Command command) {
         commandMap.remove(command.getName().toLowerCase());
-        for(String alias : command.getAliases()) {
+        for (String alias : command.getAliases()) {
             this.commandMap.remove(alias.toLowerCase());
         }
         commands.remove(command);
@@ -248,7 +248,6 @@ public class CommandDispatcher {
             // Get closest valid syntax
             if (!syntaxesSuggestions.isEmpty()) {
                 final int max = syntaxesSuggestions.firstKey(); // number of correct arguments
-
                 // Check if at least 1 argument of the syntax is correct
                 if (max > 0) {
                     // Get the data of the closest syntax

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

@@ -1,22 +1,27 @@
 package net.minestom.server.command.builder.arguments;
 
+import net.minestom.server.command.builder.arguments.minecraft.SuggestionType;
 import net.minestom.server.utils.callback.validator.StringValidator;
 import org.jetbrains.annotations.NotNull;
 import org.jetbrains.annotations.Nullable;
 
 /**
  * Same as {@link ArgumentWord} with the exception
- * that this argument can trigger {@link net.minestom.server.command.builder.Command#onDynamicWrite(String)}.
+ * that this argument can trigger {@link net.minestom.server.command.builder.Command#onDynamicWrite(String)}
+ * when the suggestion type is {@link SuggestionType#ASK_SERVER}, or any other suggestions available in the enum.
  */
 public class ArgumentDynamicWord extends Argument<String> {
 
     public static final int SPACE_ERROR = 1;
     public static final int RESTRICTION_ERROR = 2;
 
+    private SuggestionType suggestionType;
+
     private StringValidator dynamicRestriction;
 
-    public ArgumentDynamicWord(String id) {
+    public ArgumentDynamicWord(@NotNull String id, @NotNull SuggestionType suggestionType) {
         super(id);
+        this.suggestionType = suggestionType;
     }
 
     @Override
@@ -46,6 +51,18 @@ public class ArgumentDynamicWord extends Argument<String> {
         return SUCCESS;
     }
 
+    /**
+     * Gets the suggestion type of this argument.
+     * <p>
+     * Suggestions are only suggestion, this means that the end value could not be the expected one.
+     *
+     * @return this argument suggestion type
+     */
+    @NotNull
+    public SuggestionType getSuggestionType() {
+        return suggestionType;
+    }
+
     /**
      * Sets the dynamic restriction of this dynamic argument.
      * <p>

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

@@ -49,8 +49,12 @@ public class ArgumentType {
         return new ArgumentWord(id);
     }
 
+    public static ArgumentDynamicWord DynamicWord(@NotNull String id, @NotNull SuggestionType suggestionType) {
+        return new ArgumentDynamicWord(id, suggestionType);
+    }
+
     public static ArgumentDynamicWord DynamicWord(@NotNull String id) {
-        return new ArgumentDynamicWord(id);
+        return DynamicWord(id, SuggestionType.ASK_SERVER);
     }
 
     public static ArgumentStringArray StringArray(@NotNull String id) {

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

@@ -0,0 +1,22 @@
+package net.minestom.server.command.builder.arguments.minecraft;
+
+import org.jetbrains.annotations.NotNull;
+
+public enum SuggestionType {
+
+    ASK_SERVER("minecraft:ask_server"),
+    ALL_RECIPES("minecraft:all_recipes"),
+    AVAILABLE_SOUNDS("minecraft:available_sounds"),
+    SUMMONABLE_ENTITIES("minecraft:summonable_entities");
+
+    private String identifier;
+
+    SuggestionType(@NotNull String identifier) {
+        this.identifier = identifier;
+    }
+
+    @NotNull
+    public String getIdentifier() {
+        return identifier;
+    }
+}

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

@@ -6,7 +6,6 @@ import net.minestom.server.MinecraftServer;
 import net.minestom.server.utils.binary.BinaryReader;
 import net.minestom.server.utils.binary.BinaryWriter;
 import org.jetbrains.annotations.NotNull;
-import org.jetbrains.annotations.Nullable;
 
 /**
  * Represents a {@link Data} object which can be serialized and read back.
@@ -17,9 +16,6 @@ public interface SerializableData extends Data {
 
     DataManager DATA_MANAGER = MinecraftServer.getDataManager();
 
-    @Override
-    <T> void set(@NotNull String key, @Nullable T value, @Nullable Class<T> type);
-
     /**
      * Serializes the data into an array of bytes.
      * <p>

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

@@ -1122,34 +1122,6 @@ public abstract class Entity implements Viewable, EventHandler, DataContainer, P
         this.eyeHeight = eyeHeight;
     }
 
-    /**
-     * Gets if this entity is in the same chunk as the specified position.
-     *
-     * @param position the checked position chunk
-     * @return true if the entity is in the same chunk as {@code position}
-     */
-    public boolean sameChunk(@NotNull Position position) {
-        Check.notNull(position, "Position cannot be null");
-        final Position pos = getPosition();
-        final int chunkX1 = ChunkUtils.getChunkCoordinate((int) Math.floor(pos.getX()));
-        final int chunkZ1 = ChunkUtils.getChunkCoordinate((int) Math.floor(pos.getZ()));
-
-        final int chunkX2 = ChunkUtils.getChunkCoordinate((int) Math.floor(position.getX()));
-        final int chunkZ2 = ChunkUtils.getChunkCoordinate((int) Math.floor(position.getZ()));
-
-        return chunkX1 == chunkX2 && chunkZ1 == chunkZ2;
-    }
-
-    /**
-     * Gets if the entity is in the same chunk as another.
-     *
-     * @param entity the entity to check
-     * @return true if both entities are in the same chunk, false otherwise
-     */
-    public boolean sameChunk(@NotNull Entity entity) {
-        return sameChunk(entity.getPosition());
-    }
-
     /**
      * Removes the entity from the server immediately.
      * <p>
@@ -1175,17 +1147,16 @@ public abstract class Entity implements Viewable, EventHandler, DataContainer, P
     /**
      * Triggers {@link #remove()} after the specified time.
      *
-     * @param delay    the time before removing the entity
+     * @param delay    the time before removing the entity,
+     *                 0 to cancel the removing
      * @param timeUnit the unit of the delay
      */
     public void scheduleRemove(long delay, @NotNull TimeUnit timeUnit) {
-        delay = timeUnit.toMilliseconds(delay);
-
         if (delay == 0) { // Cancel the scheduled remove
             this.scheduledRemoveTime = 0;
             return;
         }
-        this.scheduledRemoveTime = System.currentTimeMillis() + delay;
+        this.scheduledRemoveTime = System.currentTimeMillis() + timeUnit.toMilliseconds(delay);
     }
 
     /**

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

@@ -66,6 +66,7 @@ public final class EntityManager {
 
             waitingPlayer.init();
 
+            // Spawn the player at Player#getRespawnPoint during the next instance tick
             spawningInstance.scheduleNextTick(waitingPlayer::setInstance);
         }
     }

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

@@ -678,40 +678,40 @@ public class Player extends LivingEntity implements CommandSender {
      * <p>
      * Be aware that because chunk operations are expensive,
      * it is possible for this method to be non-blocking when retrieving chunks is required.
-     * <p>
-     * When this method is called for the first time (during player login), the player will be teleport at {@link #getRespawnPoint()}.
      *
-     * @param instance the new instance of the player
+     * @param instance      the new player instance
+     * @param spawnPosition the new position of the player,
+     *                      can be null or {@link #getPosition()} if you do not want to teleport the player
      */
-    @Override
+    public void setInstance(@NotNull Instance instance, @Nullable Position spawnPosition) {
-    public void setInstance(@NotNull Instance instance) {
         Check.notNull(instance, "instance cannot be null!");
         Check.argCondition(this.instance == instance, "Instance should be different than the current one");
 
-        final boolean firstSpawn = this.instance == null; // TODO: Handle player reconnections, must be false in that case too
-
         // true if the chunks need to be sent to the client, can be false if the instances share the same chunks (eg SharedInstance)
         final boolean needWorldRefresh = !InstanceUtils.areLinked(this.instance, instance);
 
         if (needWorldRefresh) {
+            final boolean firstSpawn = this.instance == null; // TODO: Handle player reconnections, must be false in that case too
+
             // Remove all previous viewable chunks (from the previous instance)
             for (Chunk viewableChunk : viewableChunks) {
                 viewableChunk.removeViewer(this);
             }
+
             // Send the new dimension
             if (this.instance != null) {
                 final DimensionType instanceDimensionType = instance.getDimensionType();
                 if (dimensionType != instanceDimensionType)
                     sendDimension(instanceDimensionType);
             }
+
             // Load all the required chunks
-            final Position pos = firstSpawn ? getRespawnPoint() : position;
+            final long[] visibleChunks = ChunkUtils.getChunksInRange(spawnPosition, getChunkRange());
-            final long[] visibleChunks = ChunkUtils.getChunksInRange(pos, getChunkRange());
 
             final ChunkCallback eachCallback = chunk -> {
                 if (chunk != null) {
-                    final int chunkX = ChunkUtils.getChunkCoordinate((int) pos.getX());
+                    final int chunkX = ChunkUtils.getChunkCoordinate((int) spawnPosition.getX());
-                    final int chunkZ = ChunkUtils.getChunkCoordinate((int) pos.getZ());
+                    final int chunkZ = ChunkUtils.getChunkCoordinate((int) spawnPosition.getZ());
                     if (chunk.getChunkX() == chunkX &&
                             chunk.getChunkZ() == chunkZ) {
                         updateViewPosition(chunkX, chunkZ);
@@ -721,7 +721,7 @@ public class Player extends LivingEntity implements CommandSender {
 
             final ChunkCallback endCallback = chunk -> {
                 // This is the last chunk to be loaded , spawn player
-                spawnPlayer(instance, firstSpawn);
+                spawnPlayer(instance, spawnPosition, firstSpawn);
             };
 
             // Chunk 0;0 always needs to be loaded
@@ -732,26 +732,42 @@ public class Player extends LivingEntity implements CommandSender {
         } else {
             // The player already has the good version of all the chunks.
             // We just need to refresh his entity viewing list and add him to the instance
-            spawnPlayer(instance, false);
+            spawnPlayer(instance, spawnPosition, false);
         }
     }
 
+    /**
+     * Changes the player instance without changing its position (defaulted to {@link #getRespawnPoint()}
+     * if the player is not in any instance.
+     *
+     * @param instance the new player instance
+     * @see #setInstance(Instance, Position)
+     */
+    @Override
+    public void setInstance(@NotNull Instance instance) {
+        setInstance(instance, this.instance != null ? getPosition() : getRespawnPoint());
+    }
+
     /**
      * Used to spawn the player once the client has all the required chunks.
      * <p>
      * Does add the player to {@code instance}, remove all viewable entities and call {@link PlayerSpawnEvent}.
      * <p>
-     * UNSAFE: only called with {@link #setInstance(Instance)}.
+     * UNSAFE: only called with {@link #setInstance(Instance, Position)}.
      *
-     * @param firstSpawn true if this is the player first spawn
+     * @param spawnPosition the position to teleport the player
+     * @param firstSpawn    true if this is the player first spawn
      */
-    private void spawnPlayer(@NotNull Instance instance, boolean firstSpawn) {
+    private void spawnPlayer(@NotNull Instance instance, @Nullable Position spawnPosition, boolean firstSpawn) {
         this.viewableEntities.forEach(entity -> entity.removeViewer(this));
 
         super.setInstance(instance);
 
-        if (firstSpawn) {
+        if (spawnPosition != null && !position.isSimilar(spawnPosition)) {
-            teleport(getRespawnPoint());
+            teleport(spawnPosition,
+                    position.inSameChunk(spawnPosition) ? () -> refreshVisibleChunks(getChunk()) : null);
+        } else {
+            refreshVisibleChunks(getChunk());
         }
 
         PlayerSpawnEvent spawnEvent = new PlayerSpawnEvent(this, instance, firstSpawn);
@@ -1510,7 +1526,7 @@ public class Player extends LivingEntity implements CommandSender {
         // New chunks indexes
         final long[] updatedVisibleChunks = ChunkUtils.getChunksInRange(newChunk.toPosition(), getChunkRange());
 
-        // Find the difference between the two arrays¬
+        // Find the difference between the two arrays
         final int[] oldChunks = ArrayUtils.getDifferencesBetweenArray(lastVisibleChunks, updatedVisibleChunks);
         final int[] newChunks = ArrayUtils.getDifferencesBetweenArray(updatedVisibleChunks, lastVisibleChunks);
 

src/main/java/net/minestom/server/entity/task/EntityTask.java

@@ -1,36 +0,0 @@
-package net.minestom.server.entity.task;
-
-import net.minestom.server.entity.LivingEntity;
-
-public abstract class EntityTask {
-
-    /**
-     * Whether the task should begin executing for this entity.
-     *
-     * @param entity the entity in question.
-     * @return true if the task should start, false otherwise.
-     */
-    public abstract boolean shouldStart(LivingEntity entity);
-
-    /**
-     * Invoked when this task is about to start for this entity.
-     *
-     * @param entity the entity in question.
-     */
-    public abstract void start(LivingEntity entity);
-
-    /**
-     * Invoked when this task is being ended for this entity.
-     *
-     * @param entity the entity in question.
-     */
-    public abstract void end(LivingEntity entity);
-
-    /**
-     * Invoked each tick when this task is being executed for this entity.
-     *
-     * @param entity the entity in question.
-     */
-    public abstract void execute(LivingEntity entity);
-
-}

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

@@ -8,6 +8,7 @@ import net.minestom.server.entity.Player;
 import net.minestom.server.entity.pathfinding.PFColumnarSpace;
 import net.minestom.server.event.player.PlayerChunkLoadEvent;
 import net.minestom.server.event.player.PlayerChunkUnloadEvent;
+import net.minestom.server.instance.batch.BatchOption;
 import net.minestom.server.instance.batch.BlockBatch;
 import net.minestom.server.instance.batch.ChunkBatch;
 import net.minestom.server.instance.block.Block;
@@ -186,7 +187,7 @@ public abstract class Chunk implements Viewable, DataContainer {
      * @param z    the block Z
      * @param data the new data, can be null
      */
-    public abstract void setBlockData(int x, int y, int z, Data data);
+    public abstract void setBlockData(int x, int y, int z, @Nullable Data data);
 
     /**
      * Gets all the block entities in this chunk.
@@ -240,15 +241,22 @@ public abstract class Chunk implements Viewable, DataContainer {
     /**
      * Creates a copy of this chunk, including blocks state id, custom block id, biomes, update data.
      * <p>
-     * The instance and chunk position (X/Z) can be modified using the given arguments.
+     * The chunk position (X/Z) can be modified using the given arguments.
      *
-     * @param chunkX the new chunk X
+     * @param chunkX the chunk X of the copy
-     * @param chunkZ the new chunk Z
+     * @param chunkZ the chunk Z of the copy
      * @return a copy of this chunk with a potentially new instance and position
      */
     @NotNull
     public abstract Chunk copy(int chunkX, int chunkZ);
 
+    /**
+     * Resets the chunk, this means clearing all the data making it empty.
+     * <p>
+     * Used for {@link BatchOption#isFullChunk()}.
+     */
+    public abstract void reset();
+
     /**
      * Gets the {@link CustomBlock} at a position.
      *
@@ -314,6 +322,7 @@ public abstract class Chunk implements Viewable, DataContainer {
      *
      * @return the position of this chunk
      */
+    @NotNull
     public Position toPosition() {
         return new Position(CHUNK_SIZE_Z * getChunkX(), 0, CHUNK_SIZE_Z * getChunkZ());
     }
@@ -385,6 +394,37 @@ public abstract class Chunk implements Viewable, DataContainer {
         return fullDataPacket;
     }
 
+    /**
+     * Gets the light packet of this chunk.
+     *
+     * @return the light packet
+     */
+    @NotNull
+    public UpdateLightPacket getLightPacket() {
+        // TODO do not hardcode light
+        UpdateLightPacket updateLightPacket = new UpdateLightPacket(getIdentifier(), getLastChangeTime());
+        updateLightPacket.chunkX = getChunkX();
+        updateLightPacket.chunkZ = getChunkZ();
+        updateLightPacket.skyLightMask = 0x3FFF0;
+        updateLightPacket.blockLightMask = 0x3F;
+        updateLightPacket.emptySkyLightMask = 0x0F;
+        updateLightPacket.emptyBlockLightMask = 0x3FFC0;
+        byte[] bytes = new byte[2048];
+        Arrays.fill(bytes, (byte) 0xFF);
+        List<byte[]> temp = new ArrayList<>(14);
+        List<byte[]> temp2 = new ArrayList<>(6);
+        for (int i = 0; i < 14; ++i) {
+            temp.add(bytes);
+        }
+        for (int i = 0; i < 6; ++i) {
+            temp2.add(bytes);
+        }
+        updateLightPacket.skyLight = temp;
+        updateLightPacket.blockLight = temp2;
+
+        return updateLightPacket;
+    }
+
     /**
      * Used to verify if the chunk should still be kept in memory.
      *
@@ -468,7 +508,7 @@ public abstract class Chunk implements Viewable, DataContainer {
      *
      * @param player the player
      */
-    protected synchronized void sendChunk(@NotNull Player player) {
+    public synchronized void sendChunk(@NotNull Player player) {
         // Only send loaded chunk
         if (!isLoaded())
             return;
@@ -478,30 +518,16 @@ public abstract class Chunk implements Viewable, DataContainer {
         // Retrieve & send the buffer to the connection
         playerConnection.sendPacket(getFreshFullDataPacket());
 
-        // TODO do not hardcode light
+        playerConnection.sendPacket(getLightPacket());
-        {
+    }
-            UpdateLightPacket updateLightPacket = new UpdateLightPacket(getIdentifier(), getLastChangeTime());
-            updateLightPacket.chunkX = getChunkX();
-            updateLightPacket.chunkZ = getChunkZ();
-            updateLightPacket.skyLightMask = 0x3FFF0;
-            updateLightPacket.blockLightMask = 0x3F;
-            updateLightPacket.emptySkyLightMask = 0x0F;
-            updateLightPacket.emptyBlockLightMask = 0x3FFC0;
-            byte[] bytes = new byte[2048];
-            Arrays.fill(bytes, (byte) 0xFF);
-            List<byte[]> temp = new ArrayList<>(14);
-            List<byte[]> temp2 = new ArrayList<>(6);
-            for (int i = 0; i < 14; ++i) {
-                temp.add(bytes);
-            }
-            for (int i = 0; i < 6; ++i) {
-                temp2.add(bytes);
-            }
-            updateLightPacket.skyLight = temp;
-            updateLightPacket.blockLight = temp2;
 
-            playerConnection.sendPacket(updateLightPacket);
+    public synchronized void sendChunk() {
+        if (!isLoaded()) {
+            return;
         }
+
+        sendPacketToViewers(getFreshFullDataPacket());
+        sendPacketToViewers(getLightPacket());
     }
 
     /**

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

@@ -31,7 +31,7 @@ import java.util.Set;
 /**
  * Represents a {@link Chunk} which store each individual block in memory.
  * <p>
- * WARNING: not thread-safe
+ * WARNING: not thread-safe.
  */
 public class DynamicChunk extends Chunk {
 
@@ -408,6 +408,17 @@ public class DynamicChunk extends Chunk {
         return dynamicChunk;
     }
 
+    @Override
+    public void reset() {
+        this.blockPalette.clear();
+        this.customBlockPalette.clear();
+
+        this.blocksData.clear();
+        this.updatableBlocks.clear();
+        this.updatableBlocksLastUpdate.clear();
+        this.blockEntities.clear();
+    }
+
     private short getBlockAt(@NotNull PaletteStorage paletteStorage, int x, int y, int z) {
         return paletteStorage.getBlockAt(x, y, z);
     }

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

@@ -1,6 +1,7 @@
 package net.minestom.server.instance;
 
 import it.unimi.dsi.fastutil.longs.Long2ObjectMap;
+import it.unimi.dsi.fastutil.longs.Long2ObjectMaps;
 import it.unimi.dsi.fastutil.longs.Long2ObjectOpenHashMap;
 import net.minestom.server.MinecraftServer;
 import net.minestom.server.UpdateManager;
@@ -81,7 +82,8 @@ public abstract class Instance implements BlockModifier, EventHandler, DataConta
     protected final Set<ObjectEntity> objectEntities = new CopyOnWriteArraySet<>();
     protected final Set<ExperienceOrb> experienceOrbs = new CopyOnWriteArraySet<>();
     // Entities per chunk
-    protected final Long2ObjectMap<Set<Entity>> chunkEntities = new Long2ObjectOpenHashMap<>();
+    protected final Long2ObjectMap<Set<Entity>> chunkEntities = Long2ObjectMaps.synchronize(new Long2ObjectOpenHashMap<>());
+    private Object entitiesLock = new Object(); // Lock used to prevent the entities Set and Map to be subject to race condition
 
     // the uuid of this instance
     protected UUID uniqueId;
@@ -921,7 +923,7 @@ public abstract class Instance implements BlockModifier, EventHandler, DataConta
                 "The chunk " + chunk + " is not loaded, you can make it automatic by using Instance#enableAutoChunkLoad(true)");
         Check.argCondition(!chunk.isLoaded(), "Chunk " + chunk + " has been unloaded previously");
         final long chunkIndex = ChunkUtils.getChunkIndex(chunk.getChunkX(), chunk.getChunkZ());
-        synchronized (chunkEntities) {
+        synchronized (entitiesLock) {
             Set<Entity> entities = getEntitiesInChunk(chunkIndex);
             entities.add(entity);
             this.chunkEntities.put(chunkIndex, entities);
@@ -948,7 +950,7 @@ public abstract class Instance implements BlockModifier, EventHandler, DataConta
      * @param chunk  the chunk where the entity will be removed
      */
     public void removeEntityFromChunk(@NotNull Entity entity, @NotNull Chunk chunk) {
-        synchronized (chunkEntities) {
+        synchronized (entitiesLock) {
             final long chunkIndex = ChunkUtils.getChunkIndex(chunk.getChunkX(), chunk.getChunkZ());
             Set<Entity> entities = getEntitiesInChunk(chunkIndex);
             entities.remove(entity);
@@ -973,9 +975,7 @@ public abstract class Instance implements BlockModifier, EventHandler, DataConta
 
     @NotNull
     private Set<Entity> getEntitiesInChunk(long index) {
-        synchronized (chunkEntities) {
+        return chunkEntities.computeIfAbsent(index, i -> new CopyOnWriteArraySet<>());
-            return chunkEntities.computeIfAbsent(index, i -> new CopyOnWriteArraySet<>());
-        }
     }
 
     /**

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

@@ -1,6 +1,7 @@
 package net.minestom.server.instance;
 
 import it.unimi.dsi.fastutil.longs.Long2ObjectMap;
+import it.unimi.dsi.fastutil.longs.Long2ObjectMaps;
 import it.unimi.dsi.fastutil.longs.Long2ObjectOpenHashMap;
 import net.minestom.server.MinecraftServer;
 import net.minestom.server.data.Data;
@@ -57,7 +58,7 @@ public class InstanceContainer extends Instance {
     // the chunk generator used, can be null
     private ChunkGenerator chunkGenerator;
     // (chunk index -> chunk) map, contains all the chunks in the instance
-    private final Long2ObjectMap<Chunk> chunks = new Long2ObjectOpenHashMap<>();
+    private final Long2ObjectMap<Chunk> chunks = Long2ObjectMaps.synchronize(new Long2ObjectOpenHashMap<>());
     // contains all the chunks to remove during the next instance tick
     protected final Set<Chunk> scheduledChunksToRemove = new HashSet<>();
 
@@ -312,7 +313,7 @@ public class InstanceContainer extends Instance {
      *
      * @param blockPosition the position of the modified block
      */
-    private void executeNeighboursBlockPlacementRule(BlockPosition blockPosition) {
+    private void executeNeighboursBlockPlacementRule(@NotNull BlockPosition blockPosition) {
         for (int offsetX = -1; offsetX < 2; offsetX++) {
             for (int offsetY = -1; offsetY < 2; offsetY++) {
                 for (int offsetZ = -1; offsetZ < 2; offsetZ++) {
@@ -451,10 +452,8 @@ public class InstanceContainer extends Instance {
     @Override
     public Chunk getChunk(int chunkX, int chunkZ) {
         final long index = ChunkUtils.getChunkIndex(chunkX, chunkZ);
-        synchronized (chunks) {
+        final Chunk chunk = chunks.get(index);
-            final Chunk chunk = chunks.get(index);
+        return ChunkUtils.isLoaded(chunk) ? chunk : null;
-            return ChunkUtils.isLoaded(chunk) ? chunk : null;
-        }
     }
 
     /**
@@ -480,7 +479,7 @@ public class InstanceContainer extends Instance {
     }
 
     /**
-     * Save the instance without callback.
+     * Saves the instance without callback.
      *
      * @see #saveInstance(Runnable)
      */
@@ -495,10 +494,8 @@ public class InstanceContainer extends Instance {
 
     @Override
     public void saveChunksToStorage(@Nullable Runnable callback) {
-        synchronized (chunks) {
+        Collection<Chunk> chunksCollection = chunks.values();
-            Collection<Chunk> chunksCollection = chunks.values();
+        this.chunkLoader.saveChunks(chunksCollection, callback);
-            this.chunkLoader.saveChunks(chunksCollection, callback);
-        }
     }
 
     @Override
@@ -645,16 +642,14 @@ public class InstanceContainer extends Instance {
         copiedInstance.srcInstance = this;
         copiedInstance.lastBlockChangeTime = lastBlockChangeTime;
 
-        synchronized (chunks) {
+        for (Chunk chunk : chunks.values()) {
-            for (Chunk chunk : chunks.values()) {
+            final int chunkX = chunk.getChunkX();
-                final int chunkX = chunk.getChunkX();
+            final int chunkZ = chunk.getChunkZ();
-                final int chunkZ = chunk.getChunkZ();
 
-                final Chunk copiedChunk = chunk.copy(chunkX, chunkZ);
+            final Chunk copiedChunk = chunk.copy(chunkX, chunkZ);
 
-                copiedInstance.cacheChunk(copiedChunk);
+            copiedInstance.cacheChunk(copiedChunk);
-                UPDATE_MANAGER.signalChunkLoad(copiedInstance, chunkX, chunkZ);
+            UPDATE_MANAGER.signalChunkLoad(copiedInstance, chunkX, chunkZ);
-            }
         }
 
         return copiedInstance;
@@ -701,9 +696,7 @@ public class InstanceContainer extends Instance {
      */
     public void cacheChunk(@NotNull Chunk chunk) {
         final long index = ChunkUtils.getChunkIndex(chunk.getChunkX(), chunk.getChunkZ());
-        synchronized (chunks) {
+        this.chunks.put(index, chunk);
-            this.chunks.put(index, chunk);
-        }
     }
 
     @Override
@@ -833,12 +826,8 @@ public class InstanceContainer extends Instance {
                 });
 
                 // Clear cache
-                synchronized (chunks) {
+                this.chunks.remove(index);
-                    this.chunks.remove(index);
+                this.chunkEntities.remove(index);
-                }
-                synchronized (chunkEntities) {
-                    this.chunkEntities.remove(index);
-                }
 
                 chunk.unload();
 

src/main/java/net/minestom/server/instance/batch/BatchOption.java

@@ -0,0 +1,33 @@
+package net.minestom.server.instance.batch;
+
+import org.jetbrains.annotations.NotNull;
+
+public class BatchOption {
+
+    private boolean fullChunk = false;
+
+    public BatchOption() {
+    }
+
+    /**
+     * Gets if the batch is responsible for composing the whole chunk.
+     * <p>
+     * Having it to true means that the batch will clear the chunk data before placing the blocks.
+     *
+     * @return true if the batch is responsible for all the chunk
+     */
+    public boolean isFullChunk() {
+        return fullChunk;
+    }
+
+    /**
+     * @param fullChunk true to make this batch composes the whole chunk
+     * @return 'this' for chaining
+     * @see #isFullChunk()
+     */
+    @NotNull
+    public BatchOption setFullChunk(boolean fullChunk) {
+        this.fullChunk = fullChunk;
+        return this;
+    }
+}

src/main/java/net/minestom/server/instance/batch/BlockBatch.java

@@ -6,6 +6,8 @@ import net.minestom.server.instance.Instance;
 import net.minestom.server.instance.InstanceContainer;
 import net.minestom.server.instance.block.CustomBlock;
 import net.minestom.server.utils.block.CustomBlockUtils;
+import org.jetbrains.annotations.NotNull;
+import org.jetbrains.annotations.Nullable;
 
 import java.util.ArrayList;
 import java.util.HashMap;
@@ -23,33 +25,39 @@ import java.util.concurrent.atomic.AtomicInteger;
 public class BlockBatch implements InstanceBatch {
 
     private final InstanceContainer instance;
+    private final BatchOption batchOption;
 
     private final Map<Chunk, List<BlockData>> data = new HashMap<>();
 
-    public BlockBatch(InstanceContainer instance) {
+    public BlockBatch(@NotNull InstanceContainer instance, @NotNull BatchOption batchOption) {
         this.instance = instance;
+        this.batchOption = batchOption;
+    }
+
+    public BlockBatch(@NotNull InstanceContainer instance) {
+        this(instance, new BatchOption());
     }
 
     @Override
-    public synchronized void setBlockStateId(int x, int y, int z, short blockStateId, Data data) {
+    public synchronized void setBlockStateId(int x, int y, int z, short blockStateId, @Nullable Data data) {
         final Chunk chunk = this.instance.getChunkAt(x, z);
         addBlockData(chunk, x, y, z, blockStateId, (short) 0, data);
     }
 
     @Override
-    public void setCustomBlock(int x, int y, int z, short customBlockId, Data data) {
+    public void setCustomBlock(int x, int y, int z, short customBlockId, @Nullable Data data) {
         final Chunk chunk = this.instance.getChunkAt(x, z);
         final CustomBlock customBlock = BLOCK_MANAGER.getCustomBlock(customBlockId);
         addBlockData(chunk, x, y, z, customBlock.getDefaultBlockStateId(), customBlockId, data);
     }
 
     @Override
-    public synchronized void setSeparateBlocks(int x, int y, int z, short blockStateId, short customBlockId, Data data) {
+    public synchronized void setSeparateBlocks(int x, int y, int z, short blockStateId, short customBlockId, @Nullable Data data) {
         final Chunk chunk = this.instance.getChunkAt(x, z);
         addBlockData(chunk, x, y, z, blockStateId, customBlockId, data);
     }
 
-    private void addBlockData(Chunk chunk, int x, int y, int z, short blockStateId, short customBlockId, Data data) {
+    private void addBlockData(@NotNull Chunk chunk, int x, int y, int z, short blockStateId, short customBlockId, @Nullable Data data) {
         List<BlockData> blocksData = this.data.get(chunk);
         if (blocksData == null)
             blocksData = new ArrayList<>();
@@ -67,7 +75,7 @@ public class BlockBatch implements InstanceBatch {
         this.data.put(chunk, blocksData);
     }
 
-    public void flush(Runnable callback) {
+    public void flush(@Nullable Runnable callback) {
         synchronized (data) {
             AtomicInteger counter = new AtomicInteger();
             for (Map.Entry<Chunk, List<BlockData>> entry : data.entrySet()) {
@@ -78,12 +86,20 @@ public class BlockBatch implements InstanceBatch {
                         if (!chunk.isLoaded())
                             return;
 
+                        if (batchOption.isFullChunk()) {
+                            chunk.reset();
+                        }
+
                         for (BlockData data : dataList) {
                             data.apply(chunk);
                         }
 
                         // Refresh chunk for viewers
-                        chunk.sendChunkUpdate();
+                        if (batchOption.isFullChunk()) {
+                            chunk.sendChunk();
+                        } else {
+                            chunk.sendChunkUpdate();
+                        }
 
                         final boolean isLast = counter.incrementAndGet() == data.size();
 

src/main/java/net/minestom/server/instance/batch/ChunkBatch.java

@@ -22,7 +22,7 @@ import java.util.List;
  * use a {@link BlockBatch} instead otherwise.
  * Can be created using {@link Instance#createChunkBatch(Chunk)}.
  * <p>
- * Use chunk coordinate (0-15) instead of world's.
+ * Uses chunk coordinate (0-15) instead of world's.
  *
  * @see InstanceBatch
  */
@@ -30,6 +30,7 @@ public class ChunkBatch implements InstanceBatch {
 
     private final InstanceContainer instance;
     private final Chunk chunk;
+    private final BatchOption batchOption;
 
     private final boolean generationBatch;
 
@@ -42,9 +43,11 @@ public class ChunkBatch implements InstanceBatch {
     private Int2ObjectMap<Data> blockDataMap;
 
     public ChunkBatch(@NotNull InstanceContainer instance, @NotNull Chunk chunk,
+                      @NotNull BatchOption batchOption,
                       boolean generationBatch) {
         this.instance = instance;
         this.chunk = chunk;
+        this.batchOption = batchOption;
         this.generationBatch = generationBatch;
 
         if (!generationBatch) {
@@ -53,6 +56,11 @@ public class ChunkBatch implements InstanceBatch {
         }
     }
 
+    public ChunkBatch(@NotNull InstanceContainer instance, @NotNull Chunk chunk,
+                      boolean generationBatch) {
+        this(instance, chunk, new BatchOption(), generationBatch);
+    }
+
     @Override
     public void setBlockStateId(int x, int y, int z, short blockStateId, @Nullable Data data) {
         addBlockData((byte) x, y, (byte) z, blockStateId, (short) 0, data);
@@ -120,6 +128,10 @@ public class ChunkBatch implements InstanceBatch {
                 final List<ChunkPopulator> populators = chunkGenerator.getPopulators();
                 final boolean hasPopulator = populators != null && !populators.isEmpty();
 
+                if (batchOption.isFullChunk()) {
+                    this.chunk.reset();
+                }
+
                 chunkGenerator.generateChunkData(this, chunk.getChunkX(), chunk.getChunkZ());
 
                 if (hasPopulator) {
@@ -128,16 +140,7 @@ public class ChunkBatch implements InstanceBatch {
                     }
                 }
 
-                // Refresh chunk for viewers
+                updateChunk(callback, true);
-                this.chunk.sendChunkUpdate();
-
-                this.instance.refreshLastBlockChangeTime();
-
-                // Safe callback
-                instance.scheduleNextTick(inst -> {
-                    OptionalCallback.execute(callback, chunk);
-                });
-
             }
         });
     }
@@ -197,18 +200,7 @@ public class ChunkBatch implements InstanceBatch {
                 }
             }
 
-            // Refresh chunk for viewers
+            updateChunk(callback, safeCallback);
-            chunk.sendChunkUpdate();
-
-            this.instance.refreshLastBlockChangeTime();
-
-            if (callback != null) {
-                if (safeCallback) {
-                    this.instance.scheduleNextTick(inst -> callback.accept(chunk));
-                } else {
-                    callback.accept(chunk);
-                }
-            }
         }
     }
 
@@ -234,8 +226,26 @@ public class ChunkBatch implements InstanceBatch {
                 ChunkUtils.blockIndexToChunkPositionY(index),
                 ChunkUtils.blockIndexToChunkPositionZ(index),
                 blockId, customBlockId, data, CustomBlockUtils.hasUpdate(customBlockId));
+    }
 
+    private void updateChunk(@Nullable ChunkCallback callback, boolean safeCallback) {
 
+        // Refresh chunk for viewers
+        if (batchOption.isFullChunk()) {
+            chunk.sendChunk();
+        } else {
+            chunk.sendChunkUpdate();
+        }
+
+        this.instance.refreshLastBlockChangeTime();
+
+        if (callback != null) {
+            if (safeCallback) {
+                this.instance.scheduleNextTick(inst -> callback.accept(chunk));
+            } else {
+                callback.accept(chunk);
+            }
+        }
     }
 
 }

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

@@ -45,12 +45,12 @@ public class PaletteStorage {
     private int valuesPerLong;
     private boolean hasPalette;
 
-    private long[][] sectionBlocks = new long[CHUNK_SECTION_COUNT][0];
+    private long[][] sectionBlocks;
 
     // chunk section - palette index = block id
-    private Short2ShortLinkedOpenHashMap[] paletteBlockMaps = new Short2ShortLinkedOpenHashMap[CHUNK_SECTION_COUNT];
+    private Short2ShortLinkedOpenHashMap[] paletteBlockMaps;
     // chunk section - block id = palette index
-    private Short2ShortOpenHashMap[] blockPaletteMaps = new Short2ShortOpenHashMap[CHUNK_SECTION_COUNT];
+    private Short2ShortOpenHashMap[] blockPaletteMaps;
 
     /**
      * Creates a new palette storage.
@@ -72,6 +72,15 @@ public class PaletteStorage {
 
         this.valuesPerLong = Long.SIZE / bitsPerEntry;
         this.hasPalette = bitsPerEntry <= PALETTE_MAXIMUM_BITS;
+
+        init();
+    }
+
+    private void init() {
+        this.sectionBlocks = new long[CHUNK_SECTION_COUNT][0];
+
+        this.paletteBlockMaps = new Short2ShortLinkedOpenHashMap[CHUNK_SECTION_COUNT];
+        this.blockPaletteMaps = new Short2ShortOpenHashMap[CHUNK_SECTION_COUNT];
     }
 
     public void setBlockAt(int x, int y, int z, short blockId) {
@@ -139,6 +148,14 @@ public class PaletteStorage {
         }
     }
 
+    /**
+     * Clears all the data in the palette and data array.
+     */
+    public void clear() {
+        init();
+    }
+
+    @NotNull
     public PaletteStorage copy() {
         PaletteStorage paletteStorage = new PaletteStorage(bitsPerEntry, bitsIncrement);
         paletteStorage.sectionBlocks = sectionBlocks.clone();

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

@@ -1,5 +1,8 @@
 package net.minestom.server.utils;
 
+import net.minestom.server.utils.chunk.ChunkUtils;
+import org.jetbrains.annotations.NotNull;
+
 import java.util.Objects;
 
 /**
@@ -72,8 +75,8 @@ public class Position {
 
     /**
      * Gets the distance between 2 positions.
-     *   In cases where performance matters, {@link #getDistanceSquared(Position)} should be used
+     * In cases where performance matters, {@link #getDistanceSquared(Position)} should be used
-     *   as it does not perform the expensive Math.sqrt method.
+     * as it does not perform the expensive Math.sqrt method.
      *
      * @param position the second position
      * @return the distance between {@code this} and {@code position}
@@ -86,15 +89,15 @@ public class Position {
 
     /**
      * Gets the square distance to another position.
-    *
+     *
-    * @param position the second position
+     * @param position the second position
-    * @return the squared distance between {@code this} and {@code position}
+     * @return the squared distance between {@code this} and {@code position}
-    */
+     */
-   public float getDistanceSquared(Position position) {
+    public float getDistanceSquared(Position position) {
-       return MathUtils.square(getX() - position.getX()) +
+        return MathUtils.square(getX() - position.getX()) +
-               MathUtils.square(getY() - position.getY()) +
+                MathUtils.square(getY() - position.getY()) +
-               MathUtils.square(getZ() - position.getZ());
+                MathUtils.square(getZ() - position.getZ());
-   }
+    }
 
     /**
      * Gets a unit-vector pointing in the direction that this Location is
@@ -209,7 +212,7 @@ public class Position {
      * @param position the position to compare
      * @return true if the two positions are similar
      */
-    public boolean isSimilar(Position position) {
+    public boolean isSimilar(@NotNull Position position) {
         return Float.compare(position.x, x) == 0 &&
                 Float.compare(position.y, y) == 0 &&
                 Float.compare(position.z, z) == 0;
@@ -221,11 +224,27 @@ public class Position {
      * @param position the position to compare
      * @return true if the two positions have the same view
      */
-    public boolean hasSimilarView(Position position) {
+    public boolean hasSimilarView(@NotNull Position position) {
         return Float.compare(position.yaw, yaw) == 0 &&
                 Float.compare(position.pitch, pitch) == 0;
     }
 
+    /**
+     * Gets if two positions are in the same chunk.
+     *
+     * @param position the checked position chunk
+     * @return true if 'this' is in the same chunk as {@code position}
+     */
+    public boolean inSameChunk(@NotNull Position position) {
+        final int chunkX1 = ChunkUtils.getChunkCoordinate((int) Math.floor(getX()));
+        final int chunkZ1 = ChunkUtils.getChunkCoordinate((int) Math.floor(getZ()));
+
+        final int chunkX2 = ChunkUtils.getChunkCoordinate((int) Math.floor(position.getX()));
+        final int chunkZ2 = ChunkUtils.getChunkCoordinate((int) Math.floor(position.getZ()));
+
+        return chunkX1 == chunkX2 && chunkZ1 == chunkZ2;
+    }
+
     @Override
     public int hashCode() {
         return Objects.hash(x, y, z, yaw, pitch);

src/test/java/demo/commands/TestCommand.java

@@ -1,11 +1,12 @@
 package demo.commands;
 
+import net.minestom.server.MinecraftServer;
 import net.minestom.server.command.CommandSender;
 import net.minestom.server.command.builder.Arguments;
 import net.minestom.server.command.builder.Command;
 import net.minestom.server.command.builder.arguments.Argument;
 import net.minestom.server.command.builder.arguments.ArgumentType;
-import net.minestom.server.entity.Player;
+import net.minestom.server.command.builder.arguments.minecraft.SuggestionType;
 
 public class TestCommand extends Command {
 
@@ -13,20 +14,20 @@ public class TestCommand extends Command {
         super("testcmd");
         setDefaultExecutor(this::usage);
 
-        Argument test = ArgumentType.ItemStack("test");
+        Argument test = ArgumentType.DynamicWord("view_distance", SuggestionType.SUMMONABLE_ENTITIES);
 
         test.setCallback((source, value, error) -> {
             System.out.println("ERROR " + error);
         });
 
         setDefaultExecutor((source, args) -> {
-            System.gc();
+            //System.gc();
-            source.sendMessage("Explicit GC executed!");
+            //source.sendMessage("Explicit GC executed!");
+            MinecraftServer.setChunkViewDistance(2);
         });
 
         addSyntax((source, args) -> {
-            Player player = (Player) source;
+
-            System.out.println("ARG 1");
         }, test);
     }