Small cleanup

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

@@ -60,20 +60,20 @@ public abstract class BasicEnumGenerator extends MinestomEnumGenerator<BasicEnum
         ParameterSpec[] signature = new ParameterSpec[]{idParam};
         if (linear) {
             generator.addStaticMethod("fromId", signature, className, code -> {
-                code.beginControlFlow("if($N >= 0 && $N < values().length)", idParam, idParam)
+                        code.beginControlFlow("if($N >= 0 && $N < values().length)", idParam, idParam)
-                        .addStatement("return values()[$N]", idParam)
+                                .addStatement("return values()[$N]", idParam)
-                    .endControlFlow()
+                                .endControlFlow()
-                    .addStatement("return " + (defaultEntry == null ? "null" : identifier(defaultEntry)));
+                                .addStatement("return " + (defaultEntry == null ? "null" : identifier(defaultEntry)));
                     }
             );
         } else {
             generator.addStaticMethod("fromId", signature, className, code -> {
-                code.beginControlFlow("for($T o : values())")
+                        code.beginControlFlow("for($T o : values())")
-                        .beginControlFlow("if(o.getId() == id)")
+                                .beginControlFlow("if(o.getId() == id)")
-                            .addStatement("return o")
+                                .addStatement("return o")
-                        .endControlFlow()
+                                .endControlFlow()
-                    .endControlFlow()
+                                .endControlFlow()
-                    .addStatement("return " + (defaultEntry == null ? "null" : identifier(defaultEntry)));
+                                .addStatement("return " + (defaultEntry == null ? "null" : identifier(defaultEntry)));
                     }
             );
         }

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

@@ -108,10 +108,12 @@ public class Command {
      *
      * @param executor the executor to call when the syntax is successfully received
      * @param args     all the arguments of the syntax
+     * @return the created {@link CommandSyntax}
      */
-    public void addSyntax(@NotNull CommandExecutor executor, @NotNull Argument<?>... args) {
+    public CommandSyntax addSyntax(@NotNull CommandExecutor executor, @NotNull Argument<?>... args) {
         final CommandSyntax syntax = new CommandSyntax(executor, args);
         this.syntaxes.add(syntax);
+        return syntax;
     }
 
     /**
@@ -126,10 +128,8 @@ public class Command {
 
     /**
      * Gets the command's aliases.
-     * <p>
-     * Can be null or empty.
      *
-     * @return the command aliases
+     * @return the command aliases, can be null or empty
      */
     @Nullable
     public String[] getAliases() {
@@ -137,10 +137,10 @@ public class Command {
     }
 
     /**
-     * Gets the default {@link CommandExecutor} (which is called when there is no argument)
+     * Gets the default {@link CommandExecutor} which is called when there is no argument
      * or if no corresponding syntax has been found.
      *
-     * @return the default executor
+     * @return the default executor, null if not any
      */
     @Nullable
     public CommandExecutor getDefaultExecutor() {
@@ -150,7 +150,7 @@ public class Command {
     /**
      * Sets the default {@link CommandExecutor} (which is called when there is no argument).
      *
-     * @param executor the new default executor
+     * @param executor the new default executor, null to remove it
      */
     public void setDefaultExecutor(@Nullable CommandExecutor executor) {
         this.defaultExecutor = executor;

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

@@ -106,7 +106,7 @@ public class CommandDispatcher {
         TreeMap<Integer, CommandSuggestionHolder> syntaxesSuggestions = new TreeMap<>(Collections.reverseOrder());
 
         for (CommandSyntax syntax : syntaxes) {
-            final Argument<Object>[] arguments = syntax.getArguments();
+            final Argument<?>[] arguments = syntax.getArguments();
             final String[] argsValues = new String[arguments.length];
 
             boolean syntaxCorrect = true;
@@ -115,7 +115,7 @@ public class CommandDispatcher {
             boolean useRemaining = false;
             // Check the validity of the arguments...
             for (int argCount = 0; argCount < syntax.getArguments().length; argCount++) {
-                final Argument<Object> argument = syntax.getArguments()[argCount];
+                final Argument<?> argument = syntax.getArguments()[argCount];
                 useRemaining = argument.useRemaining();
 
                 // the correction result of the argument
@@ -200,10 +200,10 @@ public class CommandDispatcher {
 
             // Otherwise, search for the first syntax with an incorrect argument
             for (CommandSyntax syntax : validSyntaxes) {
-                final Argument<Object>[] arguments = syntax.getArguments();
+                final Argument[] arguments = syntax.getArguments();
                 final String[] argsValues = syntaxesValues.get(syntax);
                 for (int i = 0; i < arguments.length; i++) {
-                    final Argument<Object> argument = arguments[i];
+                    final Argument argument = arguments[i];
                     final String argValue = argsValues[i];
                     // Finally parse it
                     final Object parsedValue = argument.parse(argValue);
@@ -239,7 +239,7 @@ public class CommandDispatcher {
                     final int argIndex = suggestionHolder.argIndex;
 
                     // Found the closest syntax with at least 1 correct argument
-                    final Argument<Object> argument = syntax.getArguments()[argIndex];
+                    final Argument<?> argument = syntax.getArguments()[argIndex];
                     if (argument.hasErrorCallback()) {
                         result.callback = argument.getCallback();
                         result.value = argValue;
@@ -279,10 +279,10 @@ public class CommandDispatcher {
             Arguments syntaxValues = new Arguments();
             boolean fullyCorrect = true;
 
-            final Argument<Object>[] arguments = syntax.getArguments();
+            final Argument<?>[] arguments = syntax.getArguments();
             final String[] argsValues = syntaxesValues.get(syntax);
             for (int i = 0; i < arguments.length; i++) {
-                final Argument<Object> argument = arguments[i];
+                final Argument argument = arguments[i];
                 final String argValue = argsValues[i];
                 // Finally parse it
                 final Object parsedValue = argument.parse(argValue);

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

@@ -4,14 +4,15 @@ import net.minestom.server.command.builder.arguments.Argument;
 import org.jetbrains.annotations.NotNull;
 
 /**
- * Represents a syntax in {@link Command}.
+ * Represents a syntax in {@link Command}
+ * which is initialized with {@link Command#addSyntax(CommandExecutor, Argument[])}.
  */
 public class CommandSyntax {
 
-    private final Argument[] args;
+    private final Argument<?>[] args;
     private CommandExecutor executor;
 
-    protected CommandSyntax(@NotNull CommandExecutor commandExecutor, @NotNull Argument... args) {
+    protected CommandSyntax(@NotNull CommandExecutor commandExecutor, @NotNull Argument<?>... args) {
         this.executor = commandExecutor;
         this.args = args;
     }
@@ -22,7 +23,7 @@ public class CommandSyntax {
      * @return the required arguments
      */
     @NotNull
-    public Argument<Object>[] getArguments() {
+    public Argument<?>[] getArguments() {
         return args;
     }
 

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

@@ -112,7 +112,7 @@ public abstract class Argument<T> {
     /**
      * Gets the {@link ArgumentCallback} to check if the argument-specific conditions are validated or not.
      *
-     * @return the argument callback
+     * @return the argument callback, null if not any
      */
     @Nullable
     public ArgumentCallback getCallback() {
@@ -122,7 +122,7 @@ public abstract class Argument<T> {
     /**
      * Sets the {@link ArgumentCallback}.
      *
-     * @param callback the argument callback
+     * @param callback the argument callback, null to do not have one
      */
     public void setCallback(@Nullable ArgumentCallback callback) {
         this.callback = callback;

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

@@ -37,8 +37,7 @@ public class ArgumentNbtTag extends Argument<NBT> {
     @Override
     public NBT parse(@NotNull String value) {
         try {
-            NBT nbt = new SNBTParser(new StringReader(value)).parse();
+            return new SNBTParser(new StringReader(value)).parse();
-            return nbt;
         } catch (NBTException e) {
             return null;
         }

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

@@ -648,9 +648,9 @@ public abstract class Entity implements Viewable, EventHandler, DataContainer {
     /**
      * Convenient method to get the entity current chunk.
      *
-     * @return the entity chunk
+     * @return the entity chunk, can be null even if unlikely
      */
-    @NotNull
+    @Nullable
     public Chunk getChunk() {
         return instance.getChunkAt(lastX, lastZ);
     }

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

@@ -144,7 +144,7 @@ public abstract class EntityCreature extends LivingEntity {
     }
 
     @Override
-    public void setInstance(Instance instance) {
+    public void setInstance(@NotNull Instance instance) {
         super.setInstance(instance);
         this.pathFinder = new HydrazinePathFinder(pathingEntity, instance.getInstanceSpace());
     }
@@ -224,7 +224,7 @@ public abstract class EntityCreature extends LivingEntity {
     }
 
     /**
-     * Changes the entity target
+     * Changes the entity target.
      *
      * @param target the new entity target
      */

src/main/java/net/minestom/server/entity/ai/target/ClosestEntityTarget.java

@@ -7,6 +7,7 @@ import net.minestom.server.entity.ai.TargetSelector;
 import net.minestom.server.instance.Chunk;
 import net.minestom.server.instance.Instance;
 import net.minestom.server.utils.chunk.ChunkUtils;
+import org.jetbrains.annotations.NotNull;
 
 import java.util.ArrayList;
 import java.util.List;
@@ -17,11 +18,11 @@ import java.util.Set;
  */
 public class ClosestEntityTarget extends TargetSelector {
 
-    private float range;
+    private final float range;
-    private Class<? extends LivingEntity>[] entitiesTarget;
+    private final Class<? extends LivingEntity>[] entitiesTarget;
 
-    public ClosestEntityTarget(EntityCreature entityCreature, float range,
+    public ClosestEntityTarget(@NotNull EntityCreature entityCreature, float range,
-                               Class<? extends LivingEntity>... entitiesTarget) {
+                               @NotNull Class<? extends LivingEntity>... entitiesTarget) {
         super(entityCreature);
         this.range = range;
         this.entitiesTarget = entitiesTarget;
@@ -31,6 +32,10 @@ public class ClosestEntityTarget extends TargetSelector {
     public Entity findTarget() {
         final Instance instance = getEntityCreature().getInstance();
         final Chunk currentChunk = instance.getChunkAt(entityCreature.getPosition());
+        if (currentChunk == null) {
+            return null;
+        }
+
         final List<Chunk> chunks = getNeighbours(instance, currentChunk.getChunkX(), currentChunk.getChunkZ());
 
         Entity entity = null;

src/main/java/net/minestom/server/entity/type/monster/EntityGuardian.java

@@ -56,7 +56,7 @@ public class EntityGuardian extends EntityCreature implements Monster {
         return target;
     }
 
-    public void setTarget(Entity target) {
+    public void setTarget(@NotNull Entity target) {
         this.target = target;
     }
 }

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

@@ -4,6 +4,7 @@ import net.minestom.server.chat.RichMessage;
 import net.minestom.server.entity.Player;
 import net.minestom.server.event.CancellableEvent;
 import org.jetbrains.annotations.NotNull;
+import org.jetbrains.annotations.Nullable;
 
 import java.util.ArrayList;
 import java.util.Collection;
@@ -29,9 +30,9 @@ public class PlayerChatEvent extends CancellableEvent {
     /**
      * Changes the chat format.
      *
-     * @param chatFormat the custom chat format
+     * @param chatFormat the custom chat format, null to use the default one
      */
-    public void setChatFormat(@NotNull Function<PlayerChatEvent, RichMessage> chatFormat) {
+    public void setChatFormat(@Nullable Function<PlayerChatEvent, RichMessage> chatFormat) {
         this.chatFormat = chatFormat;
     }
 
@@ -81,9 +82,9 @@ public class PlayerChatEvent extends CancellableEvent {
      * <p>
      * If null, the default format will be used.
      *
-     * @return the chat format which will be used
+     * @return the chat format which will be used, null if this is the default one
      */
-    @NotNull
+    @Nullable
     public Function<PlayerChatEvent, RichMessage> getChatFormatFunction() {
         return chatFormat;
     }

src/main/java/net/minestom/server/gamedata/loottables/LootTableContainer.java

@@ -28,7 +28,7 @@ class LootTableContainer {
         return new LootTable(type, pools);
     }
 
-    private class Pool {
+    private static class Pool {
         private ConditionContainer[] conditions;
         private FunctionContainer[] functions;
         private RangeContainer rolls;

src/main/java/net/minestom/server/gamedata/loottables/LootTableManager.java

@@ -31,6 +31,7 @@ public final class LootTableManager {
 
     /**
      * Registers a condition factory to the given namespaceID
+     *
      * @param namespaceID
      * @param factory
      */
@@ -40,6 +41,7 @@ public final class LootTableManager {
 
     /**
      * Registers a loot table type to the given namespaceID
+     *
      * @param namespaceID
      * @param type
      */
@@ -49,6 +51,7 @@ public final class LootTableManager {
 
     /**
      * Registers a loot table entry type to the given namespaceID
+     *
      * @param namespaceID
      * @param type
      */
@@ -58,6 +61,7 @@ public final class LootTableManager {
 
     /**
      * Registers a loot table function to the given namespaceID
+     *
      * @param namespaceID
      * @param function
      */
@@ -66,22 +70,22 @@ public final class LootTableManager {
     }
 
     public LootTable load(NamespaceID name) throws FileNotFoundException {
-        return load(name, new FileReader(new File(ResourceGatherer.DATA_FOLDER, "data/"+name.getDomain()+"/loot_tables/"+name.getPath()+".json")));
+        return load(name, new FileReader(new File(ResourceGatherer.DATA_FOLDER, "data/" + name.getDomain() + "/loot_tables/" + name.getPath() + ".json")));
     }
 
     /**
      * Loads a loot table with the given name. Loot tables can be cached, so 'reader' is used only on cache misses
-     * @param name the name to cache the loot table with
+     *
+     * @param name   the name to cache the loot table with
      * @param reader the reader to read the loot table from, if none cached. **Will** be closed no matter the results of this call
      * @return
      */
     public LootTable load(NamespaceID name, Reader reader) {
-        try {
+        try (reader) {
             return cache.computeIfAbsent(name, _name -> create(reader));
-        } finally {
+        } catch (IOException e) {
-            try {
+            e.printStackTrace();
-                reader.close();
+            return null;
-            } catch (IOException e) {}
         }
     }
 
@@ -92,28 +96,31 @@ public final class LootTableManager {
 
     /**
      * Returns the registered table type corresponding to the given namespace ID. If none is registered, throws {@link IllegalArgumentException}
+     *
      * @param id
      * @return
      */
     public LootTableType getTableType(NamespaceID id) {
-        if(!tableTypes.containsKey(id))
+        if (!tableTypes.containsKey(id))
-            throw new IllegalArgumentException("Unknown table type: "+id);
+            throw new IllegalArgumentException("Unknown table type: " + id);
         return tableTypes.get(id);
     }
 
     /**
      * Returns the registered entry type corresponding to the given namespace ID. If none is registered, throws {@link IllegalArgumentException}
+     *
      * @param id
      * @return
      */
     public LootTableEntryType getEntryType(NamespaceID id) {
-        if(!entryTypes.containsKey(id))
+        if (!entryTypes.containsKey(id))
-            throw new IllegalArgumentException("Unknown entry type: "+id);
+            throw new IllegalArgumentException("Unknown entry type: " + id);
         return entryTypes.get(id);
     }
 
     /**
      * Returns the registered table type corresponding to the given namespace ID. If none is registered, returns {@link LootTableFunction#IDENTITY}
+     *
      * @param id
      * @return
      */

src/main/java/net/minestom/server/gamedata/loottables/entries/DynamicEntry.java

@@ -31,6 +31,6 @@ public class DynamicEntry extends LootTable.Entry {
 
     public enum Type {
         SELF,
-        CONTENTS;
+        CONTENTS
     }
 }

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

@@ -59,7 +59,9 @@ public abstract class Chunk implements Viewable, DataContainer {
 
     public static final int BIOME_COUNT = 1024; // 4x4x4 blocks group
 
+    @NotNull
     protected final Instance instance;
+    @NotNull
     protected final Biome[] biomes;
     protected final int chunkX, chunkZ;
 

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

@@ -24,6 +24,7 @@ import net.minestom.server.utils.time.UpdateOption;
 import net.minestom.server.utils.validate.Check;
 import net.minestom.server.world.biomes.Biome;
 import org.jetbrains.annotations.NotNull;
+import org.jetbrains.annotations.Nullable;
 
 import java.util.HashSet;
 import java.util.Set;
@@ -58,7 +59,7 @@ public class DynamicChunk extends Chunk {
     // Block entities
     protected final Set<Integer> blockEntities = new CopyOnWriteArraySet<>();
 
-    public DynamicChunk(Instance instance, Biome[] biomes, int chunkX, int chunkZ) {
+    public DynamicChunk(@NotNull Instance instance, @Nullable Biome[] biomes, int chunkX, int chunkZ) {
         super(instance, biomes, chunkX, chunkZ, true);
     }
 
@@ -136,16 +137,18 @@ public class DynamicChunk extends Chunk {
 
             // Update cooldown
             final UpdateOption updateOption = customBlock.getUpdateOption();
-            final long lastUpdate = updatableBlocksLastUpdate.get(index);
+            if (updateOption != null) {
-            final boolean hasCooldown = CooldownUtils.hasCooldown(time, lastUpdate, updateOption);
+                final long lastUpdate = updatableBlocksLastUpdate.get(index);
-            if (hasCooldown)
+                final boolean hasCooldown = CooldownUtils.hasCooldown(time, lastUpdate, updateOption);
-                continue;
+                if (hasCooldown)
+                    continue;
 
-            this.updatableBlocksLastUpdate.put(index, time); // Refresh last update time
+                this.updatableBlocksLastUpdate.put(index, time); // Refresh last update time
 
-            final BlockPosition blockPosition = ChunkUtils.getBlockPosition(index, chunkX, chunkZ);
+                final BlockPosition blockPosition = ChunkUtils.getBlockPosition(index, chunkX, chunkZ);
-            final Data data = getBlockData(index);
+                final Data data = getBlockData(index);
-            customBlock.update(instance, blockPosition, data);
+                customBlock.update(instance, blockPosition, data);
+            }
         }
     }
 
@@ -343,7 +346,7 @@ public class DynamicChunk extends Chunk {
                 // CHUNK DATA
                 // Chunk data
                 final boolean hasChunkData = reader.readBoolean();
-                if (hasChunkData) {
+                if (hasDataIndex && hasChunkData) {
                     SerializableData serializableData = new SerializableDataImpl();
                     serializableData.readSerializedData(reader, typeToIndexMap);
                 }
@@ -371,7 +374,7 @@ public class DynamicChunk extends Chunk {
                     {
                         final boolean hasBlockData = reader.readBoolean();
                         // Data deserializer
-                        if (hasBlockData) {
+                        if (hasDataIndex && hasBlockData) {
                             // Read the data with the deserialized index map
                             data = new SerializableDataImpl();
                             data.readSerializedData(reader, typeToIndexMap);

src/main/java/net/minestom/server/instance/block/CustomBlock.java

@@ -86,7 +86,7 @@ public abstract class CustomBlock {
      * If this is not null, {@link #update(Instance, BlockPosition, Data)}
      * should be overridden or errors with occurs.
      *
-     * @return the update option of the block
+     * @return the update option of the block, null if not any
      */
     @Nullable
     public UpdateOption getUpdateOption() {

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

@@ -74,12 +74,10 @@ public class ChatMessageListener {
 
         final ColoredText usernameText = ColoredText.of(String.format("<%s>", username));
 
-        final RichMessage richMessage = RichMessage.of(usernameText)
+        return RichMessage.of(usernameText)
                 .setHoverEvent(ChatHoverEvent.showText("Click to send a message to " + username))
                 .setClickEvent(ChatClickEvent.suggestCommand("/msg " + username + " "))
                 .append(ColoredText.of(" " + chatEvent.getMessage()));
-
-        return richMessage;
     }
 
 }

src/main/java/net/minestom/server/map/MapColors.java

@@ -347,6 +347,6 @@ public enum MapColors {
         /**
          * RGB components are divided by 10 before issuing a lookup (as with the PRECISE strategy), but saves on memory usage
          */
-        APPROXIMATE;
+        APPROXIMATE
     }
 }

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

@@ -46,7 +46,7 @@ public class AdvancementsPacket implements ServerPacket {
         public Advancement value;
 
         @Override
-        public void write(BinaryWriter writer) {
+        public void write(@NotNull BinaryWriter writer) {
             writer.writeSizedString(key);
             value.write(writer);
         }
@@ -60,7 +60,7 @@ public class AdvancementsPacket implements ServerPacket {
         public Requirement[] requirements;
 
         @Override
-        public void write(BinaryWriter writer) {
+        public void write(@NotNull BinaryWriter writer) {
             // hasParent
             writer.writeBoolean(parentIdentifier != null);
             if (parentIdentifier != null) {
@@ -94,7 +94,7 @@ public class AdvancementsPacket implements ServerPacket {
         public float y;
 
         @Override
-        public void write(BinaryWriter writer) {
+        public void write(@NotNull BinaryWriter writer) {
             writer.writeSizedString(title.toString());
             writer.writeSizedString(description.toString());
             writer.writeItemStack(icon);
@@ -114,7 +114,7 @@ public class AdvancementsPacket implements ServerPacket {
         public String[] requirements;
 
         @Override
-        public void write(BinaryWriter writer) {
+        public void write(@NotNull BinaryWriter writer) {
             writer.writeVarInt(requirements.length);
             for (String requirement : requirements) {
                 writer.writeSizedString(requirement);
@@ -127,7 +127,7 @@ public class AdvancementsPacket implements ServerPacket {
         public AdvancementProgress value;
 
         @Override
-        public void write(BinaryWriter writer) {
+        public void write(@NotNull BinaryWriter writer) {
             writer.writeSizedString(key);
             value.write(writer);
         }
@@ -137,7 +137,7 @@ public class AdvancementsPacket implements ServerPacket {
         public Criteria[] criteria;
 
         @Override
-        public void write(BinaryWriter writer) {
+        public void write(@NotNull BinaryWriter writer) {
             writer.writeVarInt(criteria.length);
             for (Criteria criterion : criteria) {
                 criterion.write(writer);
@@ -150,7 +150,7 @@ public class AdvancementsPacket implements ServerPacket {
         public CriterionProgress criterionProgress;
 
         @Override
-        public void write(BinaryWriter writer) {
+        public void write(@NotNull BinaryWriter writer) {
             writer.writeSizedString(criterionIdentifier);
             criterionProgress.write(writer);
         }
@@ -162,7 +162,7 @@ public class AdvancementsPacket implements ServerPacket {
         public long dateOfAchieving;
 
         @Override
-        public void write(BinaryWriter writer) {
+        public void write(@NotNull BinaryWriter writer) {
             writer.writeBoolean(achieved);
             if (dateOfAchieving != 0)
                 writer.writeLong(dateOfAchieving);

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

@@ -38,7 +38,7 @@ public class DeclareCommandsPacket implements ServerPacket {
         public String suggestionsType; // Only if flags 0x10
 
         @Override
-        public void write(BinaryWriter writer) {
+        public void write(@NotNull BinaryWriter writer) {
             writer.writeByte(flags);
 
             writer.writeVarIntArray(children);

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

@@ -23,8 +23,7 @@ public class MultiBlockChangePacket implements ServerPacket {
         if (blockChanges != null) {
             final int length = blockChanges.length;
             writer.writeVarInt(length);
-            for (int i = 0; i < length; i++) {
+            for (final BlockChange blockChange : blockChanges) {
-                final BlockChange blockChange = blockChanges[i];
                 writer.writeVarLong(blockChange.newBlockId << 12 | getLocalBlockPosAsShort(blockChange.positionX, blockChange.positionY, blockChange.positionZ));
             }
         } else {

src/main/java/net/minestom/server/timer/SchedulerManager.java

@@ -23,9 +23,9 @@ import java.util.concurrent.atomic.AtomicInteger;
  * <p>
  * Shutdown {@link Task} are built with {@link #buildShutdownTask(Runnable)}.
  */
-public class SchedulerManager {
+public final class SchedulerManager {
 
-    private boolean instanced;
+    private static boolean instanced;
     // A counter for all normal tasks
     private final AtomicInteger counter;
     // A counter for all shutdown tasks
@@ -47,7 +47,8 @@ public class SchedulerManager {
             throw new IllegalStateException("You cannot instantiate a SchedulerManager," +
                     " use MinecraftServer.getSchedulerManager()");
         }
-        this.instanced = true;
+        SchedulerManager.instanced = true;
+
         this.counter = new AtomicInteger();
         this.shutdownCounter = new AtomicInteger();
 
@@ -111,6 +112,7 @@ public class SchedulerManager {
         try {
             batchesPool.awaitTermination(Long.MAX_VALUE, TimeUnit.NANOSECONDS);
         } catch (InterruptedException e) {
+            e.printStackTrace();
         }
     }
 

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

@@ -105,7 +105,6 @@ public final class ArrayUtils {
      * @param supplier the supplier to fill the array
      * @param <T>      the array type
      */
-    @NotNull
     public static <T> void fill(@NotNull T[] array, @NotNull Supplier<T> supplier) {
         for (int i = 0; i < array.length; i++) {
             array[i] = supplier.get();

src/main/java/net/minestom/server/utils/time/CooldownUtils.java

@@ -1,5 +1,7 @@
 package net.minestom.server.utils.time;
 
+import org.jetbrains.annotations.NotNull;
+
 public final class CooldownUtils {
 
     private CooldownUtils() {
@@ -15,7 +17,7 @@ public final class CooldownUtils {
      * @param cooldown    the value of the cooldown
      * @return true if the cooldown is in progress, false otherwise
      */
-    public static boolean hasCooldown(long currentTime, long lastUpdate, TimeUnit timeUnit, int cooldown) {
+    public static boolean hasCooldown(long currentTime, long lastUpdate, @NotNull TimeUnit timeUnit, int cooldown) {
         final long cooldownMs = timeUnit.toMilliseconds(cooldown);
         return currentTime - lastUpdate < cooldownMs;
     }
@@ -28,7 +30,7 @@ public final class CooldownUtils {
      * @param updateOption the cooldown
      * @return true if the cooldown is in progress, false otherwise
      */
-    public static boolean hasCooldown(long currentTime, long lastUpdate, UpdateOption updateOption) {
+    public static boolean hasCooldown(long currentTime, long lastUpdate, @NotNull UpdateOption updateOption) {
         return hasCooldown(currentTime, lastUpdate, updateOption.getTimeUnit(), updateOption.getValue());
     }
 
@@ -40,7 +42,7 @@ public final class CooldownUtils {
      * @param cooldown   the value of the cooldown
      * @return true if the cooldown is in progress, false otherwise
      */
-    public static boolean hasCooldown(long lastUpdate, TimeUnit timeUnit, int cooldown) {
+    public static boolean hasCooldown(long lastUpdate, @NotNull TimeUnit timeUnit, int cooldown) {
         return hasCooldown(System.currentTimeMillis(), lastUpdate, timeUnit, cooldown);
     }
 }

src/main/java/net/minestom/server/world/biomes/Biome.java

@@ -50,7 +50,7 @@ public class Biome {
 	@Builder.Default
 	private final Precipitation precipitation = Precipitation.RAIN;
 	@Builder.Default
-	private TemperatureModifier temperature_modifier = TemperatureModifier.NONE;
+	private final TemperatureModifier temperature_modifier = TemperatureModifier.NONE;
 
 	public NBTCompound toNbt() {
 		NBTCompound nbt = new NBTCompound();