Add constant for null future

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

@@ -40,6 +40,7 @@ import net.minestom.server.potion.TimedPotion;
 import net.minestom.server.tag.Tag;
 import net.minestom.server.tag.TagHandler;
 import net.minestom.server.thread.ThreadProvider;
+import net.minestom.server.utils.async.AsyncUtils;
 import net.minestom.server.utils.chunk.ChunkUtils;
 import net.minestom.server.utils.entity.EntityUtils;
 import net.minestom.server.utils.player.PlayerUtils;
@@ -844,8 +845,8 @@ public class Entity implements Viewable, Tickable, EventHandler<EntityEvent>, Da
      *
      * @param instance      the new instance of the entity
      * @param spawnPosition the spawn position for the entity.
-     * @throws IllegalStateException if {@code instance} has not been registered in {@link InstanceManager}
      * @return
+     * @throws IllegalStateException if {@code instance} has not been registered in {@link InstanceManager}
      */
     public CompletableFuture<Void> setInstance(@NotNull Instance instance, @NotNull Pos spawnPosition) {
         Check.stateCondition(!instance.isRegistered(),
@@ -860,7 +861,7 @@ public class Entity implements Viewable, Tickable, EventHandler<EntityEvent>, Da
         instance.UNSAFE_addEntity(this);
         spawn();
         EventDispatcher.call(new EntitySpawnEvent(this, instance));
-        return CompletableFuture.completedFuture(null);
+        return AsyncUtils.NULL_FUTURE;
     }
 
     public CompletableFuture<Void> setInstance(@NotNull Instance instance, @NotNull Point spawnPosition) {

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

@@ -69,7 +69,7 @@ import net.minestom.server.sound.SoundCategory;
 import net.minestom.server.sound.SoundEvent;
 import net.minestom.server.stat.PlayerStatistic;
 import net.minestom.server.utils.*;
-import net.minestom.server.utils.chunk.ChunkCallback;
+import net.minestom.server.utils.async.AsyncUtils;
 import net.minestom.server.utils.chunk.ChunkUtils;
 import net.minestom.server.utils.entity.EntityUtils;
 import net.minestom.server.utils.identity.NamedAndIdentified;
@@ -519,7 +519,8 @@ public class Player extends LivingEntity implements CommandSender, Localizable,
      * <p>
      * Be aware that because chunk operations are expensive,
      * it is possible for this method to be non-blocking when retrieving chunks is required.
-     *  @param instance      the new player instance
+     *
+     * @param instance      the new player instance
      * @param spawnPosition the new position of the player
      * @return
      */
@@ -550,7 +551,7 @@ public class Player extends LivingEntity implements CommandSender, Localizable,
             // 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, spawnPosition, false, false, false);
-            return CompletableFuture.completedFuture(null);
+            return AsyncUtils.NULL_FUTURE;
         }
     }
 

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

@@ -5,6 +5,7 @@ import net.minestom.server.exception.ExceptionManager;
 import net.minestom.server.instance.block.Block;
 import net.minestom.server.instance.block.BlockHandler;
 import net.minestom.server.instance.block.BlockManager;
+import net.minestom.server.utils.async.AsyncUtils;
 import net.minestom.server.world.biomes.Biome;
 import net.minestom.server.world.biomes.BiomeManager;
 import org.jetbrains.annotations.NotNull;
@@ -196,7 +197,7 @@ public class AnvilLoader implements IChunkLoader {
                 } catch (AnvilException | IOException e) {
                     LOGGER.error("Failed to save chunk " + chunkX + ", " + chunkZ, e);
                     EXCEPTION_MANAGER.handleException(e);
-                    return CompletableFuture.completedFuture(null);
+                    return AsyncUtils.NULL_FUTURE;
                 }
             }
         }
@@ -206,7 +207,7 @@ public class AnvilLoader implements IChunkLoader {
         } catch (AnvilException | IOException e) {
             LOGGER.error("Failed to save chunk " + chunkX + ", " + chunkZ, e);
             EXCEPTION_MANAGER.handleException(e);
-            return CompletableFuture.completedFuture(null);
+            return AsyncUtils.NULL_FUTURE;
         }
         save(chunk, column);
         try {
@@ -215,9 +216,9 @@ public class AnvilLoader implements IChunkLoader {
         } catch (IOException e) {
             LOGGER.error("Failed to save chunk " + chunkX + ", " + chunkZ, e);
             EXCEPTION_MANAGER.handleException(e);
-            return CompletableFuture.completedFuture(null);
+            return AsyncUtils.NULL_FUTURE;
         }
-        return CompletableFuture.completedFuture(null);
+        return AsyncUtils.NULL_FUTURE;
     }
 
     private void save(Chunk chunk, ChunkColumn chunkColumn) {

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

@@ -1,6 +1,7 @@
 package net.minestom.server.instance;
 
 import net.minestom.server.MinecraftServer;
+import net.minestom.server.utils.async.AsyncUtils;
 import net.minestom.server.utils.thread.MinestomThread;
 import org.jetbrains.annotations.NotNull;
 import org.jetbrains.annotations.Nullable;
@@ -55,7 +56,7 @@ public interface IChunkLoader {
             } catch (InterruptedException e) {
                 MinecraftServer.getExceptionManager().handleException(e);
             }
-            return CompletableFuture.completedFuture(null);
+            return AsyncUtils.NULL_FUTURE;
         } else {
             CompletableFuture<Void> completableFuture = new CompletableFuture<>();
             AtomicInteger counter = new AtomicInteger();

src/main/java/net/minestom/server/utils/async/AsyncUtils.java

@@ -6,6 +6,7 @@ import org.jetbrains.annotations.NotNull;
 import java.util.concurrent.CompletableFuture;
 
 public final class AsyncUtils {
+    public static final CompletableFuture<Void> NULL_FUTURE = CompletableFuture.completedFuture(null);
 
     public static @NotNull CompletableFuture<Void> runAsync(@NotNull Runnable runnable) {
         return CompletableFuture.runAsync(() -> {
@@ -16,5 +17,4 @@ public final class AsyncUtils {
             }
         });
     }
-
 }