More comments + cleanup

src/main/java/net/minestom/server/collision/BoundingBox.java

@@ -57,9 +57,9 @@ public class BoundingBox {
         float minZ = z;
         float maxZ = z + offsetZ;
 
-        boolean checkX = getMinX() < maxX && getMaxX() > minX;
+        final boolean checkX = getMinX() < maxX && getMaxX() > minX;
-        boolean checkY = getMinY() < maxY && getMaxY() > minY;
+        final boolean checkY = getMinY() < maxY && getMaxY() > minY;
-        boolean checkZ = getMinZ() < maxZ && getMaxZ() > minZ;
+        final boolean checkZ = getMinZ() < maxZ && getMaxZ() > minZ;
 
         return checkX && checkY && checkZ;
     }
@@ -75,6 +75,8 @@ public class BoundingBox {
     }
 
     /**
+     * Create a new bounding box linked to the same entity with expanded size
+     *
      * @param x the X offset
      * @param y the Y offset
      * @param z the Z offset
@@ -85,6 +87,8 @@ public class BoundingBox {
     }
 
     /**
+     * Create a new bounding box linked to the same entity with contracted size
+     *
      * @param x the X offset
      * @param y the Y offset
      * @param z the Z offset

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

@@ -29,14 +29,38 @@ public class Data {
 
     protected ConcurrentHashMap<String, Object> data = new ConcurrentHashMap();
 
+    /**
+     * Set a value to a specific key
+     *
+     * @param key   the key
+     * @param value the value object
+     * @param type  the value type
+     * @param <T>   the value generic
+     */
     public <T> void set(String key, T value, Class<T> type) {
         this.data.put(key, value);
     }
 
+    /**
+     * Retrieve a value based on its key
+     *
+     * @param key the key
+     * @param <T> the value type
+     * @return the data associated with the key
+     * @throws NullPointerException if the key is not found
+     */
     public <T> T get(String key) {
         return (T) data.get(key);
     }
 
+    /**
+     * Retrieve a value based on its key, give a default value if not found
+     *
+     * @param key          the key
+     * @param defaultValue the value to return if the key is not found
+     * @param <T>          the value type
+     * @return {@link #get(String)} if found, {@code defaultValue} otherwise
+     */
     public <T> T getOrDefault(String key, T defaultValue) {
         return (T) data.getOrDefault(key, defaultValue);
     }

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

@@ -16,6 +16,17 @@ public class SerializableData extends Data {
 
     private ConcurrentHashMap<String, Class> dataType = new ConcurrentHashMap<>();
 
+    /**
+     * Set a value to a specific key
+     * <p>
+     * WARNING: the type needs to be registered in {@link DataManager}
+     *
+     * @param key   the key
+     * @param value the value object
+     * @param type  the value type
+     * @param <T>   the value generic
+     * @throws UnsupportedOperationException if {@code type} is not registered in {@link DataManager}
+     */
     @Override
     public <T> void set(String key, T value, Class<T> type) {
         if (DATA_MANAGER.getDataType(type) == null) {
@@ -34,6 +45,15 @@ public class SerializableData extends Data {
         return data;
     }
 
+    /**
+     * Serialize the data into an array of bytes
+     * <p>
+     * Use {@link net.minestom.server.reader.DataReader#readData(byte[])}
+     * to convert it back
+     *
+     * @return the array representation of this data object
+     * @throws IOException if an error occur when serializing the data
+     */
     public byte[] getSerializedData() throws IOException {
         ByteArrayOutputStream output = new ByteArrayOutputStream();
         DataOutputStream dos = new DataOutputStream(output);

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

@@ -929,10 +929,10 @@ public abstract class Entity implements Viewable, EventHandler, DataContainer {
             }
         }
 
-        Instance instance = getInstance();
+        final Instance instance = getInstance();
         if (instance != null) {
-            Chunk lastChunk = instance.getChunkAt(lastX, lastZ);
+            final Chunk lastChunk = instance.getChunkAt(lastX, lastZ);
-            Chunk newChunk = instance.getChunkAt(x, z);
+            final Chunk newChunk = instance.getChunkAt(x, z);
             if (lastChunk != null && newChunk != null && lastChunk != newChunk) {
                 synchronized (instance) {
                     instance.removeEntityFromChunk(this, lastChunk);
@@ -952,24 +952,24 @@ public abstract class Entity implements Viewable, EventHandler, DataContainer {
     }
 
     private void updateView(Chunk lastChunk, Chunk newChunk) {
-        boolean isPlayer = this instanceof Player;
+        final boolean isPlayer = this instanceof Player;
 
         if (isPlayer)
             ((Player) this).onChunkChange(lastChunk, newChunk); // Refresh loaded chunk
 
         // Refresh entity viewable list
-        long[] lastVisibleChunksEntity = ChunkUtils.getChunksInRange(new Position(16 * lastChunk.getChunkX(), 0, 16 * lastChunk.getChunkZ()), MinecraftServer.ENTITY_VIEW_DISTANCE);
+        final long[] lastVisibleChunksEntity = ChunkUtils.getChunksInRange(new Position(16 * lastChunk.getChunkX(), 0, 16 * lastChunk.getChunkZ()), MinecraftServer.ENTITY_VIEW_DISTANCE);
-        long[] updatedVisibleChunksEntity = ChunkUtils.getChunksInRange(new Position(16 * newChunk.getChunkX(), 0, 16 * newChunk.getChunkZ()), MinecraftServer.ENTITY_VIEW_DISTANCE);
+        final long[] updatedVisibleChunksEntity = ChunkUtils.getChunksInRange(new Position(16 * newChunk.getChunkX(), 0, 16 * newChunk.getChunkZ()), MinecraftServer.ENTITY_VIEW_DISTANCE);
 
-        int[] oldChunksEntity = ArrayUtils.getDifferencesBetweenArray(lastVisibleChunksEntity, updatedVisibleChunksEntity);
+        final int[] oldChunksEntity = ArrayUtils.getDifferencesBetweenArray(lastVisibleChunksEntity, updatedVisibleChunksEntity);
         for (int index : oldChunksEntity) {
-            int[] chunkPos = ChunkUtils.getChunkCoord(lastVisibleChunksEntity[index]);
+            final int[] chunkPos = ChunkUtils.getChunkCoord(lastVisibleChunksEntity[index]);
-            Chunk chunk = instance.getChunk(chunkPos[0], chunkPos[1]);
+            final Chunk chunk = instance.getChunk(chunkPos[0], chunkPos[1]);
             if (chunk == null)
                 continue;
             instance.getChunkEntities(chunk).forEach(ent -> {
                 if (ent instanceof Player) {
-                    Player player = (Player) ent;
+                    final Player player = (Player) ent;
                     if (isAutoViewable())
                         removeViewer(player);
                     if (isPlayer) {
@@ -981,10 +981,10 @@ public abstract class Entity implements Viewable, EventHandler, DataContainer {
             });
         }
 
-        int[] newChunksEntity = ArrayUtils.getDifferencesBetweenArray(updatedVisibleChunksEntity, lastVisibleChunksEntity);
+        final int[] newChunksEntity = ArrayUtils.getDifferencesBetweenArray(updatedVisibleChunksEntity, lastVisibleChunksEntity);
         for (int index : newChunksEntity) {
-            int[] chunkPos = ChunkUtils.getChunkCoord(updatedVisibleChunksEntity[index]);
+            final int[] chunkPos = ChunkUtils.getChunkCoord(updatedVisibleChunksEntity[index]);
-            Chunk chunk = instance.getChunk(chunkPos[0], chunkPos[1]);
+            final Chunk chunk = instance.getChunk(chunkPos[0], chunkPos[1]);
             if (chunk == null)
                 continue;
             instance.getChunkEntities(chunk).forEach(ent -> {
@@ -1066,12 +1066,12 @@ public abstract class Entity implements Viewable, EventHandler, DataContainer {
      */
     public boolean sameChunk(Position position) {
         Check.notNull(position, "Position cannot be null");
-        Position pos = getPosition();
+        final Position pos = getPosition();
-        int chunkX1 = ChunkUtils.getChunkCoordinate((int) Math.floor(pos.getX()));
+        final int chunkX1 = ChunkUtils.getChunkCoordinate((int) Math.floor(pos.getX()));
-        int chunkZ1 = ChunkUtils.getChunkCoordinate((int) Math.floor(pos.getZ()));
+        final int chunkZ1 = ChunkUtils.getChunkCoordinate((int) Math.floor(pos.getZ()));
 
-        int chunkX2 = ChunkUtils.getChunkCoordinate((int) Math.floor(position.getX()));
+        final int chunkX2 = ChunkUtils.getChunkCoordinate((int) Math.floor(position.getX()));
-        int chunkZ2 = ChunkUtils.getChunkCoordinate((int) Math.floor(position.getZ()));
+        final int chunkZ2 = ChunkUtils.getChunkCoordinate((int) Math.floor(position.getZ()));
 
         return chunkX1 == chunkX2 && chunkZ1 == chunkZ2;
     }

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

@@ -63,24 +63,24 @@ public abstract class EntityCreature extends LivingEntity {
      * @param updateView should the entity move its head toward the position?
      */
     public void move(float x, float y, float z, boolean updateView) {
-        Position position = getPosition();
+        final Position position = getPosition();
         Position newPosition = new Position();
         // Calculate collisions boxes
         onGround = CollisionUtils.handlePhysics(this, new Vector(x, y, z), newPosition, new Vector());
         // Refresh target position
-        float newX = newPosition.getX();
+        final float newX = newPosition.getX();
-        float newY = newPosition.getY();
+        final float newY = newPosition.getY();
-        float newZ = newPosition.getZ();
+        final float newZ = newPosition.getZ();
 
         // Creatures cannot move in unload chunk
         if (ChunkUtils.isChunkUnloaded(getInstance(), newX, newZ))
             return;
 
-        float lastYaw = position.getYaw();
+        final float lastYaw = position.getYaw();
-        float radians = (float) Math.atan2(newZ - position.getZ(), newX - position.getX());
+        final float radians = (float) Math.atan2(newZ - position.getZ(), newX - position.getX());
 
-        float yaw = (float) (radians * (180.0 / Math.PI)) - 90;
+        final float yaw = (float) (radians * (180.0 / Math.PI)) - 90;
-        float pitch = position.getPitch(); // TODO
+        final float pitch = position.getPitch(); // TODO
 
         final short deltaX = (short) ((newX * 32 - position.getX() * 32) * 128);
         final short deltaY = (short) ((newY * 32 - position.getY() * 32) * 128);
@@ -289,14 +289,14 @@ public abstract class EntityCreature extends LivingEntity {
      * @param speed     define how far the entity will move
      */
     public void moveTowards(Position direction, float speed) {
-        float radians = (float) Math.atan2(direction.getZ() - position.getZ(), direction.getX() - position.getX());
+        final float radians = (float) Math.atan2(direction.getZ() - position.getZ(), direction.getX() - position.getX());
-        float speedX = (float) (Math.cos(radians) * speed);
+        final float speedX = (float) (Math.cos(radians) * speed);
-        float speedZ = (float) (Math.sin(radians) * speed);
+        final float speedZ = (float) (Math.sin(radians) * speed);
         move(speedX, 0, speedZ, true);
     }
 
     private void setNextPathPosition() {
-        BlockPosition blockPosition = blockPositions.pollFirst();
+        final BlockPosition blockPosition = blockPositions.pollFirst();
 
         if (blockPosition == null) {
             this.blockPositions = null;
@@ -312,7 +312,7 @@ public abstract class EntityCreature extends LivingEntity {
     private void pathProgress() {
         if (blockPositions != null) {
             if (targetPosition != null) {
-                float distance = getPosition().getDistance(targetPosition);
+                final float distance = getPosition().getDistance(targetPosition);
                 //System.out.println("test: "+distance);
                 if (distance < 1f) {
                     setNextPathPosition();

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

@@ -33,7 +33,7 @@ public final class EntityManager {
 
             PlayerLoginEvent loginEvent = new PlayerLoginEvent(playerCache);
             playerCache.callEvent(PlayerLoginEvent.class, loginEvent);
-            Instance spawningInstance = loginEvent.getSpawningInstance();
+            final Instance spawningInstance = loginEvent.getSpawningInstance();
 
             Check.notNull(spawningInstance, "You need to specify a spawning instance in the PlayerLoginEvent");
 
@@ -68,8 +68,8 @@ public final class EntityManager {
         // Add him to the list and change his username/uuid if changed
         this.waitingPlayers.add(player);
 
-        String username = playerPreLoginEvent.getUsername();
+        final String username = playerPreLoginEvent.getUsername();
-        UUID uuid = playerPreLoginEvent.getPlayerUuid();
+        final UUID uuid = playerPreLoginEvent.getPlayerUuid();
 
         player.setUsername(username);
         player.setUuid(uuid);

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

@@ -68,8 +68,8 @@ public class ItemEntity extends ObjectEntity {
                 (mergeUpdateOption == null || !CooldownUtils.hasCooldown(time, lastMergeCheck, mergeUpdateOption))) {
             this.lastMergeCheck = time;
 
-            Chunk chunk = instance.getChunkAt(getPosition());
+            final Chunk chunk = instance.getChunkAt(getPosition());
-            Set<Entity> entities = instance.getChunkEntities(chunk);
+            final Set<Entity> entities = instance.getChunkEntities(chunk);
             for (Entity entity : entities) {
                 if (entity instanceof ItemEntity) {
 

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

@@ -453,7 +453,7 @@ public abstract class LivingEntity extends Entity implements EquipmentHandler {
         EntityPropertiesPacket propertiesPacket = new EntityPropertiesPacket();
         propertiesPacket.entityId = getEntityId();
 
-        int length = Attribute.values().length;
+        final int length = Attribute.values().length;
         EntityPropertiesPacket.Property[] properties = new EntityPropertiesPacket.Property[length];
         for (int i = 0; i < length; i++) {
             EntityPropertiesPacket.Property property = new EntityPropertiesPacket.Property();

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

@@ -30,7 +30,7 @@ public abstract class ObjectEntity extends Entity {
 
     @Override
     public boolean addViewer(Player player) {
-        boolean result = super.addViewer(player);
+        final boolean result = super.addViewer(player);
         if (!result)
             return false;
 

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

@@ -270,7 +270,7 @@ public class Player extends LivingEntity implements CommandSender {
             return false;
 
         // Compute final heart based on health and additional hearts
-        boolean result = super.damage(type, value);
+        final boolean result = super.damage(type, value);
         if (result) {
             lastDamageSource = type;
         }
@@ -301,7 +301,7 @@ public class Player extends LivingEntity implements CommandSender {
         // Target block stage
         if (targetCustomBlock != null) {
             final byte animationCount = 10;
-            long since = time - targetBlockTime;
+            final long since = time - targetBlockTime;
             byte stage = (byte) (since / (blockBreakTime / animationCount));
             stage = MathUtils.setBetween(stage, (byte) -1, animationCount);
             if (stage != targetLastStage) {
@@ -315,12 +315,12 @@ public class Player extends LivingEntity implements CommandSender {
         }
 
         // Experience orb pickup
-        Chunk chunk = instance.getChunkAt(getPosition()); // TODO check surrounding chunks
+        final Chunk chunk = instance.getChunkAt(getPosition()); // TODO check surrounding chunks
-        Set<Entity> entities = instance.getChunkEntities(chunk);
+        final Set<Entity> entities = instance.getChunkEntities(chunk);
         for (Entity entity : entities) {
             if (entity instanceof ExperienceOrb) {
-                ExperienceOrb experienceOrb = (ExperienceOrb) entity;
+                final ExperienceOrb experienceOrb = (ExperienceOrb) entity;
-                BoundingBox itemBoundingBox = experienceOrb.getBoundingBox();
+                final BoundingBox itemBoundingBox = experienceOrb.getBoundingBox();
                 if (expandedBoundingBox.intersect(itemBoundingBox)) {
                     synchronized (experienceOrb) {
                         if (experienceOrb.shouldRemove() || experienceOrb.isRemoveScheduled())
@@ -344,11 +344,11 @@ public class Player extends LivingEntity implements CommandSender {
                 ItemUpdateStateEvent itemUpdateStateEvent = callItemUpdateStateEvent(true);
 
                 // Refresh hand
-                boolean isOffHand = itemUpdateStateEvent.getHand() == Player.Hand.OFF;
+                final boolean isOffHand = itemUpdateStateEvent.getHand() == Player.Hand.OFF;
                 refreshActiveHand(false, isOffHand, false);
 
-                ItemStack foodItem = itemUpdateStateEvent.getItemStack();
+                final ItemStack foodItem = itemUpdateStateEvent.getItemStack();
-                boolean isFood = foodItem.getMaterial().isFood();
+                final boolean isFood = foodItem.getMaterial().isFood();
 
                 if (isFood) {
                     PlayerEatEvent playerEatEvent = new PlayerEatEvent(this, foodItem);
@@ -508,7 +508,7 @@ public class Player extends LivingEntity implements CommandSender {
         if (player == this)
             return false;
 
-        boolean result = super.addViewer(player);
+        final boolean result = super.addViewer(player);
         if (!result)
             return false;
 
@@ -537,7 +537,7 @@ public class Player extends LivingEntity implements CommandSender {
         Check.notNull(instance, "instance cannot be null!");
         Check.argCondition(this.instance == instance, "Instance should be different than the current one");
 
-        boolean firstSpawn = this.instance == null; // TODO: Handle player reconnections, must be false in that case too
+        final boolean firstSpawn = this.instance == null; // TODO: Handle player reconnections, must be false in that case too
         for (Chunk viewableChunk : viewableChunks) {
             viewableChunk.removeViewer(this);
         }
@@ -549,14 +549,14 @@ public class Player extends LivingEntity implements CommandSender {
                 sendDimension(instanceDimensionType);
         }
 
-        long[] visibleChunks = ChunkUtils.getChunksInRange(position, getChunkRange());
+        final long[] visibleChunks = ChunkUtils.getChunksInRange(position, getChunkRange());
-        int length = visibleChunks.length;
+        final int length = visibleChunks.length;
 
         AtomicInteger counter = new AtomicInteger(0);
         for (int i = 0; i < length; i++) {
-            int[] chunkPos = ChunkUtils.getChunkCoord(visibleChunks[i]);
+            final int[] chunkPos = ChunkUtils.getChunkCoord(visibleChunks[i]);
-            int chunkX = chunkPos[0];
+            final int chunkX = chunkPos[0];
-            int chunkZ = chunkPos[1];
+            final int chunkZ = chunkPos[1];
             Consumer<Chunk> callback = (chunk) -> {
                 if (chunk != null) {
                     viewableChunks.add(chunk);
@@ -564,7 +564,7 @@ public class Player extends LivingEntity implements CommandSender {
                     instance.sendChunk(this, chunk);
                     updateViewPosition(chunk);
                 }
-                boolean isLast = counter.get() == length - 1;
+                final boolean isLast = counter.get() == length - 1;
                 if (isLast) {
                     // This is the last chunk to be loaded , spawn player
                     super.setInstance(instance);
@@ -606,7 +606,7 @@ public class Player extends LivingEntity implements CommandSender {
 
     /**
      * Send a {@link BlockBreakAnimationPacket} packet to the player and his viewers
-     * Setting {@code destroyStage} to -1 reset the break animation
+     * Setting {@code destroyStage} to -1 resets the break animation
      *
      * @param blockPosition the position of the block
      * @param destroyStage  the destroy stage
@@ -899,6 +899,8 @@ public class Player extends LivingEntity implements CommandSender {
 
     /**
      * Change the player skin
+     * <p>
+     * This does remove the player for all viewers to spawn it again with the correct new skin
      *
      * @param skin the player skin, null to reset it to his {@link #getUuid()} default skin
      */
@@ -908,8 +910,8 @@ public class Player extends LivingEntity implements CommandSender {
         DestroyEntitiesPacket destroyEntitiesPacket = new DestroyEntitiesPacket();
         destroyEntitiesPacket.entityIds = new int[]{getEntityId()};
 
-        PlayerInfoPacket removePlayerPacket = getRemovePlayerToList();
+        final PlayerInfoPacket removePlayerPacket = getRemovePlayerToList();
-        PlayerInfoPacket addPlayerPacket = getAddPlayerToList();
+        final PlayerInfoPacket addPlayerPacket = getAddPlayerToList();
 
         RespawnPacket respawnPacket = new RespawnPacket();
         respawnPacket.dimensionType = getDimensionType();
@@ -1007,7 +1009,6 @@ public class Player extends LivingEntity implements CommandSender {
     public void setResourcePack(ResourcePack resourcePack) {
         Check.notNull(resourcePack, "The resource pack cannot be null");
         final String url = resourcePack.getUrl();
-        Check.notNull(url, "The resource pack url cannot be null");
         final String hash = resourcePack.getHash();
 
         ResourcePackSendPacket resourcePackSendPacket = new ResourcePackSendPacket();
@@ -1157,15 +1158,24 @@ public class Player extends LivingEntity implements CommandSender {
         playerConnection.sendPacket(setExperiencePacket);
     }
 
+    /**
+     * Called when the player changes chunk (move from one to another)
+     * <p>
+     * It does remove and add the player from the chunks viewers list when removed or added
+     * It also calls the events {@link PlayerChunkUnloadEvent} and {@link PlayerChunkLoadEvent}
+     *
+     * @param lastChunk the last player chunk
+     * @param newChunk  the current/new player chunk
+     */
     protected void onChunkChange(Chunk lastChunk, Chunk newChunk) {
-        long[] lastVisibleChunks = ChunkUtils.getChunksInRange(new Position(16 * lastChunk.getChunkX(), 0, 16 * lastChunk.getChunkZ()), MinecraftServer.CHUNK_VIEW_DISTANCE);
+        final long[] lastVisibleChunks = ChunkUtils.getChunksInRange(new Position(16 * lastChunk.getChunkX(), 0, 16 * lastChunk.getChunkZ()), MinecraftServer.CHUNK_VIEW_DISTANCE);
-        long[] updatedVisibleChunks = ChunkUtils.getChunksInRange(new Position(16 * newChunk.getChunkX(), 0, 16 * newChunk.getChunkZ()), MinecraftServer.CHUNK_VIEW_DISTANCE);
+        final long[] updatedVisibleChunks = ChunkUtils.getChunksInRange(new Position(16 * newChunk.getChunkX(), 0, 16 * newChunk.getChunkZ()), MinecraftServer.CHUNK_VIEW_DISTANCE);
-        int[] oldChunks = ArrayUtils.getDifferencesBetweenArray(lastVisibleChunks, updatedVisibleChunks);
+        final int[] oldChunks = ArrayUtils.getDifferencesBetweenArray(lastVisibleChunks, updatedVisibleChunks);
-        int[] newChunks = ArrayUtils.getDifferencesBetweenArray(updatedVisibleChunks, lastVisibleChunks);
+        final int[] newChunks = ArrayUtils.getDifferencesBetweenArray(updatedVisibleChunks, lastVisibleChunks);
 
         // Unload old chunks
         for (int index : oldChunks) {
-            int[] chunkPos = ChunkUtils.getChunkCoord(lastVisibleChunks[index]);
+            final int[] chunkPos = ChunkUtils.getChunkCoord(lastVisibleChunks[index]);
             UnloadChunkPacket unloadChunkPacket = new UnloadChunkPacket();
             unloadChunkPacket.chunkX = chunkPos[0];
             unloadChunkPacket.chunkZ = chunkPos[1];
@@ -1180,8 +1190,8 @@ public class Player extends LivingEntity implements CommandSender {
 
         // Load new chunks
         for (int i = 0; i < newChunks.length; i++) {
-            int index = newChunks[i];
+            final int index = newChunks[i];
-            int[] chunkPos = ChunkUtils.getChunkCoord(updatedVisibleChunks[index]);
+            final int[] chunkPos = ChunkUtils.getChunkCoord(updatedVisibleChunks[index]);
             instance.loadOptionalChunk(chunkPos[0], chunkPos[1], chunk -> {
                 if (chunk == null) {
                     // Cannot load chunk (auto load is not enabled)
@@ -1567,7 +1577,8 @@ public class Player extends LivingEntity implements CommandSender {
         this.permissionLevel = permissionLevel;
 
         // Magic values: https://wiki.vg/Entity_statuses#Player
-        byte permissionLevelStatus = (byte) (24 + permissionLevel);
+        // TODO remove magic values
+        final byte permissionLevelStatus = (byte) (24 + permissionLevel);
         triggerStatus(permissionLevelStatus);
     }
 
@@ -1580,7 +1591,8 @@ public class Player extends LivingEntity implements CommandSender {
         this.reducedDebugScreenInformation = reduced;
 
         // Magic values: https://wiki.vg/Entity_statuses#Player
-        byte debugScreenStatus = (byte) (reduced ? 22 : 23);
+        // TODO remove magic values
+        final byte debugScreenStatus = (byte) (reduced ? 22 : 23);
         triggerStatus(debugScreenStatus);
     }
 

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

@@ -14,8 +14,8 @@ import java.util.Iterator;
  */
 public class PlayerSkin {
 
-    private String textures;
+    private final String textures;
-    private String signature;
+    private final String signature;
 
     public PlayerSkin(String textures, String signature) {
         this.textures = textures;

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

@@ -351,7 +351,7 @@ public abstract class Instance implements BlockModifier, EventHandler, DataConta
         if (chunk == null)
             return new HashSet<>();
 
-        long index = ChunkUtils.getChunkIndex(chunk.getChunkX(), chunk.getChunkZ());
+        final long index = ChunkUtils.getChunkIndex(chunk.getChunkX(), chunk.getChunkZ());
         return Collections.unmodifiableSet(getEntitiesInChunk(index));
     }
 

src/main/java/net/minestom/server/reader/DataReader.java

@@ -1,15 +1,29 @@
 package net.minestom.server.reader;
 
 import io.netty.buffer.ByteBuf;
+import io.netty.buffer.Unpooled;
 import net.minestom.server.MinecraftServer;
 import net.minestom.server.data.DataManager;
 import net.minestom.server.data.SerializableData;
 import net.minestom.server.network.packet.PacketReader;
 
+/**
+ * Class used to convert an array of bytes to a {@link SerializableData}
+ * <p>
+ * WARNING: the {@link DataManager} needs to have all the required types as the {@link SerializableData} has
+ */
 public class DataReader {
 
     private static final DataManager DATA_MANAGER = MinecraftServer.getDataManager();
 
+    /**
+     * Convert a buffer into a {@link SerializableData}
+     * <p>
+     * WARNING: the {@link DataManager} needs to have all the required types as the {@link SerializableData} has
+     *
+     * @param buffer the data
+     * @return a {@link SerializableData} based on the data input
+     */
     public static SerializableData readData(ByteBuf buffer) {
         SerializableData data = new SerializableData();
         try {
@@ -50,4 +64,15 @@ public class DataReader {
         return data;
     }
 
+    /**
+     * Convert a bytes array to a {@link SerializableData}
+     *
+     * @param data the data
+     * @return a {@link SerializableData} based on the data input
+     * @see #readData(ByteBuf)
+     */
+    public static SerializableData readData(byte[] data) {
+        return readData(Unpooled.wrappedBuffer(data));
+    }
+
 }

src/main/java/net/minestom/server/resourcepack/ResourcePack.java

@@ -1,5 +1,7 @@
 package net.minestom.server.resourcepack;
 
+import net.minestom.server.utils.validate.Check;
+
 /**
  * Represent a resource pack which can be send to a player
  */
@@ -9,6 +11,7 @@ public class ResourcePack {
     private String hash;
 
     public ResourcePack(String url, String hash) {
+        Check.notNull(url, "The resource pack url cannot be null");
         this.url = url;
         // Optional, set to empty if null
         this.hash = hash == null ? "" : hash;