Make utility classes final and not constructable.

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

@@ -4,7 +4,11 @@ import it.unimi.dsi.fastutil.ints.IntList;
 
 import java.util.function.Supplier;
 
-public class ArrayUtils {
+public final class ArrayUtils {
+
+    private ArrayUtils() {
+
+    }
 
     public static byte[] concenateByteArrays(byte[]... arrays) {
         int totalLength = 0;

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

@@ -1,6 +1,10 @@
 package net.minestom.server.utils;
 
-public class MathUtils {
+public final class MathUtils {
+
+    private MathUtils() {
+
+    }
 
     public static int square(int num) {
         return num * num;
@@ -66,5 +70,4 @@ public class MathUtils {
     public static float setBetween(float number, float min, float max) {
         return number > max ? max : number < min ? min : number;
     }
-
 }

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

@@ -26,10 +26,14 @@ import java.util.Map;
 import java.util.UUID;
 
 // for lack of a better name
-public class NBTUtils {
+public final class NBTUtils {
 
     private final static Logger LOGGER = LoggerFactory.getLogger(NBTUtils.class);
 
+    private NBTUtils() {
+
+    }
+
     /**
      * Loads all the items from the 'items' list into the given inventory
      *

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

@@ -5,7 +5,11 @@ import io.netty.buffer.Unpooled;
 import net.minestom.server.network.packet.PacketWriter;
 import net.minestom.server.network.packet.server.ServerPacket;
 
-public class PacketUtils {
+public final class PacketUtils {
+
+    private PacketUtils() {
+
+    }
 
     public static void writePacket(ByteBuf buf, ServerPacket packet) {
         PacketWriter writer = new PacketWriter();

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

@@ -1,6 +1,10 @@
 package net.minestom.server.utils;
 
-public class SerializerUtils {
+public final class SerializerUtils {
+
+    private SerializerUtils() {
+
+    }
 
     public static long positionToLong(int x, int y, int z) {
         return (((long) x & 0x3FFFFFF) << 38) | (((long) z & 0x3FFFFFF) << 12) | ((long) y & 0xFFF);

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

@@ -5,7 +5,11 @@ import net.minestom.server.instance.Chunk;
 import net.minestom.server.network.packet.PacketWriter;
 import net.minestom.server.utils.buffer.BufferWrapper;
 
-public class Utils {
+public final class Utils {
+
+    private Utils() {
+
+    }
 
     public static int getVarIntSize(int input) {
         return (input & 0xFFFFFF80) == 0

src/main/java/net/minestom/server/utils/advancement/AdvancementUtils.java

@@ -2,7 +2,11 @@ package net.minestom.server.utils.advancement;
 
 import net.minestom.server.network.packet.server.play.AdvancementsPacket;
 
-public class AdvancementUtils {
+public final class AdvancementUtils {
+
+    private AdvancementUtils() {
+
+    }
 
     /**
      * Get an {@link AdvancementsPacket} which remove the specified identifiers
@@ -19,5 +23,4 @@ public class AdvancementUtils {
 
         return advancementsPacket;
     }
-
 }

src/main/java/net/minestom/server/utils/buffer/BufferUtils.java

@@ -4,9 +4,13 @@ import com.github.pbbl.heap.ByteBufferPool;
 
 import java.nio.ByteBuffer;
 
-public class BufferUtils {
+public final class BufferUtils {
 
-    private static ByteBufferPool pool = new ByteBufferPool();
+    private static final ByteBufferPool pool = new ByteBufferPool();
+
+    private BufferUtils() {
+
+    }
 
     public static BufferWrapper getBuffer(int size) {
         return new BufferWrapper(pool.take(size));
@@ -15,5 +19,4 @@ public class BufferUtils {
     protected static void giveBuffer(ByteBuffer byteBuffer) {
         pool.give(byteBuffer);
     }
-
 }

src/main/java/net/minestom/server/utils/buffer/BufferWrapper.java

@@ -6,7 +6,7 @@ import java.nio.ByteBuffer;
 
 public class BufferWrapper {
 
-    private ByteBuffer byteBuffer;
+    private final ByteBuffer byteBuffer;
     private int size;
 
     protected BufferWrapper(ByteBuffer byteBuffer) {

src/main/java/net/minestom/server/utils/chunk/ChunkUtils.java

@@ -6,7 +6,11 @@ import net.minestom.server.utils.BlockPosition;
 import net.minestom.server.utils.MathUtils;
 import net.minestom.server.utils.Position;
 
-public class ChunkUtils {
+public final class ChunkUtils {
+
+    private ChunkUtils() {
+
+    }
 
     /**
      * @param chunk the chunk to check
@@ -136,5 +140,4 @@ public class ChunkUtils {
     public static int[] indexToChunkPosition(int index) {
         return indexToPosition(index, 0, 0);
     }
-
 }

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

@@ -9,7 +9,11 @@ import net.minestom.server.utils.BlockPosition;
 import net.minestom.server.utils.Position;
 import net.minestom.server.utils.chunk.ChunkUtils;
 
-public class EntityUtils {
+public final class EntityUtils {
+
+    private EntityUtils() {
+
+    }
 
     public static boolean areVisible(Entity ent1, Entity ent2) {
         if (ent1.getInstance() == null || ent2.getInstance() == null)

src/main/java/net/minestom/server/utils/inventory/PlayerInventoryUtils.java

@@ -1,6 +1,6 @@
 package net.minestom.server.utils.inventory;
 
-public class PlayerInventoryUtils {
+public final class PlayerInventoryUtils {
 
     public static final int OFFSET = 9;
 
@@ -16,6 +16,10 @@ public class PlayerInventoryUtils {
     public static final int BOOTS_SLOT = 44;
     public static final int OFFHAND_SLOT = 45;
 
+    private PlayerInventoryUtils() {
+
+    }
+
     /**
      * Convert a packet slot to an internal one
      *

src/main/java/net/minestom/server/utils/item/ItemStackUtils.java

@@ -2,7 +2,11 @@ package net.minestom.server.utils.item;
 
 import net.minestom.server.item.ItemStack;
 
-public class ItemStackUtils {
+public final class ItemStackUtils {
+
+    private ItemStackUtils() {
+
+    }
 
     /**
      * Ensure that the returned ItemStack won't be null
@@ -24,5 +28,4 @@ public class ItemStackUtils {
     public static boolean isVisible(ItemStack itemStack) {
         return itemStack != null && !itemStack.isAir();
     }
-
 }

src/main/java/net/minestom/server/utils/player/PlayerUtils.java

@@ -5,7 +5,11 @@ import net.minestom.server.entity.Player;
 import net.minestom.server.network.player.NettyPlayerConnection;
 import net.minestom.server.network.player.PlayerConnection;
 
-public class PlayerUtils {
+public final class PlayerUtils {
+
+    private PlayerUtils() {
+
+    }
 
     public static boolean isNettyClient(PlayerConnection playerConnection) {
         return playerConnection instanceof NettyPlayerConnection;

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

@@ -1,6 +1,10 @@
 package net.minestom.server.utils.time;
 
-public class CooldownUtils {
+public final class CooldownUtils {
+
+    private CooldownUtils() {
+
+    }
 
     /**
      * Get if something is in cooldown based on the current time
@@ -39,5 +43,4 @@ public class CooldownUtils {
     public static boolean hasCooldown(long lastUpdate, TimeUnit timeUnit, int cooldown) {
         return hasCooldown(System.currentTimeMillis(), lastUpdate, timeUnit, cooldown);
     }
-
 }

src/main/java/net/minestom/server/utils/url/URLUtils.java

@@ -7,7 +7,11 @@ import java.io.InputStreamReader;
 import java.net.HttpURLConnection;
 import java.net.URL;
 
-public class URLUtils {
+public final class URLUtils {
+
+    private URLUtils() {
+
+    }
 
     public static String getText(String url) throws IOException {
         HttpURLConnection connection = (HttpURLConnection) new URL(url).openConnection();
@@ -36,5 +40,4 @@ public class URLUtils {
 
         return response.toString();
     }
-
 }