Prefer nullable over optional

src/generators/java/net/minestom/codegen/blocks/BlockEnumGenerator.java

@@ -35,7 +35,7 @@ public class BlockEnumGenerator extends MinestomEnumGenerator<BlockContainer> {
     private final String targetVersion;
     private final File targetFolder;
 
-    private CodeBlock.Builder staticBlock = CodeBlock.builder();
+    private final CodeBlock.Builder staticBlock = CodeBlock.builder();
 
 
     public static void main(String[] args) throws IOException {
@@ -161,8 +161,6 @@ public class BlockEnumGenerator extends MinestomEnumGenerator<BlockContainer> {
             }
 
             return blocks;
-        } catch (IOException e) {
-            throw e;
         }
     }
 
@@ -178,8 +176,6 @@ public class BlockEnumGenerator extends MinestomEnumGenerator<BlockContainer> {
         try (BufferedReader bufferedReader = new BufferedReader(new FileReader(blockFile))) {
             PrismarineJSBlock[] blocks = gson.fromJson(bufferedReader, PrismarineJSBlock[].class);
             return Arrays.asList(blocks);
-        } catch (IOException e) {
-            throw e;
         }
     }
 

src/generators/java/net/minestom/codegen/items/ItemEnumGenerator.java

@@ -85,8 +85,6 @@ public class ItemEnumGenerator extends MinestomEnumGenerator<ItemContainer> {
                 items.add(item);
             }
             return items;
-        } catch (IOException e) {
-            throw e;
         }
     }
 

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

@@ -39,7 +39,7 @@ public interface CommandSender extends PermissionHandler {
      * */
     default void sendMessage(@NotNull JsonMessage text) {
         if (this instanceof Player) {
-            ((Player) this).sendMessage((JsonMessage) text);
+            this.sendMessage(text);
         } else {
             sendMessage(text.getRawMessage());
         }

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

@@ -536,7 +536,7 @@ public class Player extends LivingEntity implements CommandSender {
 
             // #buildDeathScreenText can return null, check here
             if (deathText != null) {
-                CombatEventPacket deathPacket = CombatEventPacket.death(this, Optional.empty(), deathText);
+                CombatEventPacket deathPacket = CombatEventPacket.death(this, null, deathText);
                 playerConnection.sendPacket(deathPacket);
             }
 

src/main/java/net/minestom/server/extras/selfmodification/MinestomExtensionClassLoader.java

@@ -58,8 +58,7 @@ public class MinestomExtensionClassLoader extends HierarchyClassLoader {
         } catch (ClassNotFoundException e) {
             for(MinestomExtensionClassLoader child : children) {
                 try {
-                    Class<?> loaded = child.loadClassAsChild(name, resolve);
-                    return loaded;
+                    return child.loadClassAsChild(name, resolve);
                 } catch (ClassNotFoundException e1) {
                     // move on to next child
                 }

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

@@ -31,19 +31,19 @@ public class CombatEventPacket implements ServerPacket {
         return packet;
     }
 
-    public static CombatEventPacket end(int durationInTicks, Optional<Entity> opponent) {
+    public static CombatEventPacket end(int durationInTicks, Entity opponent) {
         CombatEventPacket packet = new CombatEventPacket();
         packet.type = EventType.END_COMBAT;
         packet.duration = durationInTicks;
-        packet.opponent = opponent.map(Entity::getEntityId).orElse(-1);
+        packet.opponent = opponent != null ? opponent.getEntityId() : -1;
         return packet;
     }
 
-    public static CombatEventPacket death(Player player, Optional<Entity> killer, JsonMessage message) {
+    public static CombatEventPacket death(Player player, Entity killer, JsonMessage message) {
         CombatEventPacket packet = new CombatEventPacket();
         packet.type = EventType.DEATH;
         packet.playerID = player.getEntityId();
-        packet.opponent = killer.map(Entity::getEntityId).orElse(-1);
+        packet.opponent = killer != null ? killer.getEntityId() : -1;
         packet.deathMessage = message;
         return packet;
     }

src/main/java/net/minestom/server/utils/entity/EntityFinder.java

@@ -281,20 +281,20 @@ public class EntityFinder {
                     closestDistance = distance;
                 }
             }
-            return Arrays.asList(entity);
+            return Collections.singletonList(entity);
         } else if (targetSelector == TargetSelector.RANDOM_PLAYER) {
             Collection<Player> instancePlayers = instance != null ?
                     instance.getPlayers() : MinecraftServer.getConnectionManager().getOnlinePlayers();
             final int index = ThreadLocalRandom.current().nextInt(instancePlayers.size());
             final Player player = instancePlayers.stream().skip(index).findFirst().orElseThrow();
-            return Arrays.asList(player);
+            return Collections.singletonList(player);
         } else if (targetSelector == TargetSelector.ALL_PLAYERS) {
             return new ArrayList<>(instance != null ?
                     instance.getPlayers() : MinecraftServer.getConnectionManager().getOnlinePlayers());
         } else if (targetSelector == TargetSelector.ALL_ENTITIES) {
             return new ArrayList<>(instance.getEntities());
         } else if (targetSelector == TargetSelector.SELF) {
-            return Arrays.asList(self);
+            return Collections.singletonList(self);
         }
         throw new IllegalStateException("Weird thing happened");
     }

src/test/java/demo/commands/DimensionCommand.java

@@ -36,8 +36,7 @@ public class DimensionCommand implements CommandProcessor {
         //    targetDimensionType = DimensionType.OVERWORLD;
         //}
 
-        DimensionType finalTargetDimensionType = targetDimensionType;
-        Optional<Instance> targetInstance = MinecraftServer.getInstanceManager().getInstances().stream().filter(in -> in.getDimensionType() == finalTargetDimensionType).findFirst();
+        Optional<Instance> targetInstance = MinecraftServer.getInstanceManager().getInstances().stream().filter(in -> in.getDimensionType() == targetDimensionType).findFirst();
         if (targetInstance.isPresent()) {
             player.sendMessage("You were in " + instance.getDimensionType());
             player.setInstance(targetInstance.get());

src/test/java/demo/commands/ReloadExtensionCommand.java

@@ -25,11 +25,10 @@ public class ReloadExtensionCommand extends Command {
     private static String[] extensionsName;
 
     static {
-        List<String> extensionsName = MinecraftServer.getExtensionManager().getExtensions()
+        ReloadExtensionCommand.extensionsName = MinecraftServer.getExtensionManager().getExtensions()
                 .stream()
                 .map(extension -> extension.getDescription().getName())
-                .collect(Collectors.toList());
-        ReloadExtensionCommand.extensionsName = extensionsName.toArray(new String[0]);
+                .toArray(String[]::new);
     }
 
     public ReloadExtensionCommand() {