Minor clean up

bukkit/src/main/java/com/github/games647/fastlogin/bukkit/command/ToggleCommand.java

@@ -80,7 +80,7 @@ public abstract class ToggleCommand implements CommandExecutor {
             plugin.getBungeeManager().sendPluginMessage((PluginMessageRecipient) invoker, message);
         } else {
             Optional<? extends Player> optPlayer = Bukkit.getServer().getOnlinePlayers().stream().findFirst();
-            if (!optPlayer.isPresent()) {
+            if (optPlayer.isEmpty()) {
                 plugin.getLog().info("No player online to send a plugin message to the proxy");
                 return;
             }

bukkit/src/main/java/com/github/games647/fastlogin/bukkit/listener/protocollib/EncryptionUtil.java

@@ -58,8 +58,8 @@ import java.time.Instant;
 import java.util.Arrays;
 import java.util.Base64;
 import java.util.Base64.Encoder;
-import java.util.Random;
 import java.util.UUID;
+import java.util.random.RandomGenerator;
 
 /**
  * Encryption and decryption minecraft util for connection between servers
@@ -116,7 +116,7 @@ final class EncryptionUtil {
      * @param random random generator
      * @return a token with 4 bytes long
      */
-    public static byte[] generateVerifyToken(Random random) {
+    public static byte[] generateVerifyToken(RandomGenerator random) {
         byte[] token = new byte[VERIFY_TOKEN_LENGTH];
         random.nextBytes(token);
         return token;

bukkit/src/main/java/com/github/games647/fastlogin/bukkit/listener/protocollib/ProtocolLibListener.java

@@ -204,7 +204,7 @@ public class ProtocolLibListener extends PacketAdapter {
                 Either<byte[], ?> either = packet.getSpecificModifier(Either.class).read(0);
                 if (clientPublicKey == null) {
                     Optional<byte[]> left = either.left();
-                    if (!left.isPresent()) {
+                    if (left.isEmpty()) {
                         plugin.getLog().error("No verify token sent if requested without player signed key {}", sender);
                         return false;
                     }
@@ -212,7 +212,7 @@ public class ProtocolLibListener extends PacketAdapter {
                     return EncryptionUtil.verifyNonce(expectedToken, keyPair.getPrivate(), left.get());
                 } else {
                     Optional<?> optSignatureData = either.right();
-                    if (!optSignatureData.isPresent()) {
+                    if (optSignatureData.isEmpty()) {
                         plugin.getLog().error("No signature given to sent player signing key {}", sender);
                         return false;
                     }

bukkit/src/test/java/com/github/games647/fastlogin/bukkit/listener/protocollib/EncryptionUtilTest.java

@@ -60,7 +60,7 @@ class EncryptionUtilTest {
 
     @Test
     void testVerifyToken() {
-        val random = ThreadLocalRandom.current();
+        @SuppressWarnings("SharedThreadLocalRandom") val random = ThreadLocalRandom.current();
         byte[] token = EncryptionUtil.generateVerifyToken(random);
 
         assertAll(

bukkit/src/test/java/com/github/games647/fastlogin/bukkit/listener/protocollib/ResourceLoader.java

@@ -50,6 +50,10 @@ import java.util.Base64;
 
 public class ResourceLoader {
 
+    private ResourceLoader() {
+        // Utility
+    }
+
     public static RSAPrivateKey parsePrivateKey(String keySpec)
         throws IOException, NoSuchAlgorithmException, InvalidKeySpecException {
         try (