Update minimum java version to 21

api/build.gradle.kts

@@ -59,7 +59,7 @@ tasks {
 
         val o = options as StandardJavadocDocletOptions
         o.encoding = "UTF-8"
-        o.source = "17"
+        o.source = "21"
 
         o.use()
         o.links(

build.gradle.kts

@@ -12,7 +12,7 @@ subprojects {
 
     java {
         toolchain {
-            languageVersion.set(JavaLanguageVersion.of(17))
+            languageVersion.set(JavaLanguageVersion.of(21))
         }
     }
 

gradle/libs.versions.toml

@@ -2,25 +2,25 @@
 configurate3 = "3.7.3"
 configurate4 = "4.1.2"
 flare = "2.0.1"
-log4j = "2.24.3"
+log4j = "2.25.2"
 netty = "4.2.7.Final"
 
 [plugins]
 fill = "io.papermc.fill.gradle:1.0.3"
 indra-publishing = "net.kyori.indra.publishing:2.0.6"
-shadow = "com.gradleup.shadow:8.3.6"
+shadow = "com.gradleup.shadow:9.1.0"
 spotless = "com.diffplug.spotless:6.25.0"
 
 [libraries]
 adventure-bom = "net.kyori:adventure-bom:4.25.0"
 adventure-text-serializer-json-legacy-impl = "net.kyori:adventure-text-serializer-json-legacy-impl:4.25.0"
-adventure-facet = "net.kyori:adventure-platform-facet:4.3.4"
+adventure-facet = "net.kyori:adventure-platform-facet:4.4.1"
 asm = "org.ow2.asm:asm:9.8"
 auto-service = "com.google.auto.service:auto-service:1.0.1"
 auto-service-annotations = "com.google.auto.service:auto-service-annotations:1.0.1"
 brigadier = "com.velocitypowered:velocity-brigadier:1.0.0-SNAPSHOT"
-bstats = "org.bstats:bstats-base:3.0.3"
-caffeine = "com.github.ben-manes.caffeine:caffeine:3.1.8"
+bstats = "org.bstats:bstats-base:3.1.0"
+caffeine = "com.github.ben-manes.caffeine:caffeine:3.2.2"
 checker-qual = "org.checkerframework:checker-qual:3.42.0"
 checkstyle = "com.puppycrawl.tools:checkstyle:10.9.3"
 completablefutures = "com.spotify:completable-futures:0.3.6"
@@ -34,13 +34,13 @@ disruptor = "com.lmax:disruptor:4.0.0"
 fastutil = "it.unimi.dsi:fastutil:8.5.15"
 flare-core = { module = "space.vectrix.flare:flare", version.ref = "flare" }
 flare-fastutil = { module = "space.vectrix.flare:flare-fastutil", version.ref = "flare" }
-jline = "org.jline:jline-terminal-jansi:3.30.2"
+jline = "org.jline:jline-terminal-jansi:3.30.6"
 jopt = "net.sf.jopt-simple:jopt-simple:5.0.4"
 junit = "org.junit.jupiter:junit-jupiter:5.10.2"
 jspecify = "org.jspecify:jspecify:0.3.0"
 kyori-ansi = "net.kyori:ansi:1.1.1"
-guava = "com.google.guava:guava:25.1-jre"
-gson = "com.google.code.gson:gson:2.10.1"
+guava = "com.google.guava:guava:33.3.1-jre"
+gson = "com.google.code.gson:gson:2.11.0"
 guice = "com.google.inject:guice:6.0.0"
 lmbda = "org.lanternpowered:lmbda:2.0.0"
 log4j-api = { module = "org.apache.logging.log4j:log4j-api", version.ref = "log4j" }
@@ -56,7 +56,7 @@ netty-handler = { module = "io.netty:netty-handler", version.ref = "netty" }
 netty-transport-native-epoll = { module = "io.netty:netty-transport-native-epoll", version.ref = "netty" }
 netty-transport-native-kqueue = { module = "io.netty:netty-transport-native-kqueue", version.ref = "netty" }
 netty-transport-native-iouring = { module = "io.netty:netty-transport-native-io_uring", version.ref = "netty" }
-nightconfig = "com.electronwill.night-config:toml:3.6.7"
+nightconfig = "com.electronwill.night-config:toml:3.8.3"
 slf4j = "org.slf4j:slf4j-api:2.0.17"
 snakeyaml = "org.yaml:snakeyaml:1.33"
 spotbugs-annotations = "com.github.spotbugs:spotbugs-annotations:4.7.3"

proxy/build.gradle.kts

@@ -10,7 +10,7 @@ plugins {
 
 application {
     mainClass.set("com.velocitypowered.proxy.Velocity")
-    applicationDefaultJvmArgs += listOf("-Dvelocity.packet-decode-logging=true");
+    applicationDefaultJvmArgs += listOf("-Dvelocity.packet-decode-logging=true")
 }
 
 tasks {
@@ -28,6 +28,9 @@ tasks {
 
     shadowJar {
         transform(Log4j2PluginsCacheFileTransformer::class.java)
+        filesMatching("META-INF/org/apache/logging/log4j/core/config/plugins/**") {
+            duplicatesStrategy = DuplicatesStrategy.INCLUDE
+        }
 
         // Exclude all the collection types we don"t intend to use
         exclude("it/unimi/dsi/fastutil/booleans/**")
@@ -131,7 +134,6 @@ fill {
 dependencies {
     implementation(project(":velocity-api"))
     implementation(project(":velocity-native"))
-    implementation(project(":velocity-proxy-log4j2-plugin"))
 
     implementation(libs.bundles.log4j)
     implementation(libs.kyori.ansi)
@@ -168,4 +170,5 @@ dependencies {
     testImplementation(libs.mockito)
 
     annotationProcessor(libs.auto.service)
+    annotationProcessor(libs.log4j.core)
 }

proxy/src/main/java/com/velocitypowered/proxy/command/SuggestionsProvider.java

@@ -344,7 +344,7 @@ private ParseResults<S> parseHints(final CommandNode<S> node, final StringReader
           return 0;
         });
       }
-      return potentials.get(0);
+      return potentials.getFirst();
     }
     return new ParseResults<>(contextSoFar, originalReader, Collections.emptyMap());
   }

proxy/src/main/java/com/velocitypowered/proxy/command/VelocityCommandManager.java

@@ -140,7 +140,7 @@ public void register(final CommandMeta meta, final Command command) {
               command + " implements multiple registrable Command subinterfaces: "
                       + implementedInterfaces);
     } else {
-      this.internalRegister(commandRegistrars.get(0), command, meta);
+      this.internalRegister(commandRegistrars.getFirst(), command, meta);
     }
   }
 

proxy/src/main/java/com/velocitypowered/proxy/command/VelocityCommands.java

@@ -70,33 +70,34 @@ public static CommandNode<CommandSource> wrap(final CommandNode<CommandSource> d
       maybeCommand = VelocityBrigadierCommandWrapper.wrap(delegate.getCommand(), registrant);
     }
 
-    if (delegate instanceof LiteralCommandNode<CommandSource> lcn) {
-      var literalBuilder = shallowCopyAsBuilder(lcn, delegate.getName(), true);
-      literalBuilder.executes(maybeCommand);
-      // we also need to wrap any children
-      for (final CommandNode<CommandSource> child : delegate.getChildren()) {
-        literalBuilder.then(wrap(child, registrant));
+    return switch (delegate) {
+      case LiteralCommandNode<CommandSource> lcn -> {
+        var literalBuilder = shallowCopyAsBuilder(lcn, delegate.getName(), true);
+        literalBuilder.executes(maybeCommand);
+        // we also need to wrap any children
+        for (final CommandNode<CommandSource> child : delegate.getChildren()) {
+          literalBuilder.then(wrap(child, registrant));
+        }
+        if (delegate.getRedirect() != null) {
+          literalBuilder.redirect(wrap(delegate.getRedirect(), registrant));
+        }
+        yield literalBuilder.build();
       }
-      if (delegate.getRedirect() != null) {
-        literalBuilder.redirect(wrap(delegate.getRedirect(), registrant));
+      case VelocityArgumentCommandNode<CommandSource, ?> vacn -> vacn.withCommand(maybeCommand)
+              .withRedirect(delegate.getRedirect() != null ? wrap(delegate.getRedirect(), registrant) : null);
+      case ArgumentCommandNode<CommandSource, ?> node -> {
+        var argBuilder = node.createBuilder().executes(maybeCommand);
+        // we also need to wrap any children
+        for (final CommandNode<CommandSource> child : delegate.getChildren()) {
+          argBuilder.then(wrap(child, registrant));
+        }
+        if (delegate.getRedirect() != null) {
+          argBuilder.redirect(wrap(delegate.getRedirect(), registrant));
+        }
+        yield argBuilder.build();
       }
-      return literalBuilder.build();
-    } else if (delegate instanceof VelocityArgumentCommandNode<CommandSource, ?> vacn) {
-      return vacn.withCommand(maybeCommand)
-          .withRedirect(delegate.getRedirect() != null ? wrap(delegate.getRedirect(), registrant) : null);
-    } else if (delegate instanceof ArgumentCommandNode) {
-      var argBuilder = delegate.createBuilder().executes(maybeCommand);
-      // we also need to wrap any children
-      for (final CommandNode<CommandSource> child : delegate.getChildren()) {
-        argBuilder.then(wrap(child, registrant));
-      }
-      if (delegate.getRedirect() != null) {
-        argBuilder.redirect(wrap(delegate.getRedirect(), registrant));
-      }
-      return argBuilder.build();
-    } else {
-      throw new IllegalArgumentException("Unsupported node type: " + delegate.getClass());
-    }
+      default -> throw new IllegalArgumentException("Unsupported node type: " + delegate.getClass());
+    };
   }
 
   // Normalization
@@ -133,7 +134,7 @@ public static String readAlias(final List<? extends ParsedCommandNode<?>> nodes)
     if (nodes.isEmpty()) {
       throw new IllegalArgumentException("Cannot read alias from empty node list");
     }
-    return nodes.get(0).getNode().getName();
+    return nodes.getFirst().getNode().getName();
   }
 
   public static final String ARGS_NODE_NAME = "arguments";

proxy/src/main/java/com/velocitypowered/proxy/command/brigadier/VelocityArgumentCommandNode.java

@@ -118,14 +118,12 @@ public boolean equals(final Object o) {
     if (this == o) {
       return true;
     }
-    if (!(o instanceof VelocityArgumentCommandNode)) {
+    if (!(o instanceof VelocityArgumentCommandNode that)) {
       return false;
     }
-    if (!super.equals(o)) {
+    if (!super.equals(that)) {
       return false;
     }
-
-    final VelocityArgumentCommandNode<?, ?> that = (VelocityArgumentCommandNode<?, ?>) o;
     return this.type.equals(that.type);
   }
 

proxy/src/main/java/com/velocitypowered/proxy/command/builtin/VelocityCommand.java

@@ -242,7 +242,7 @@ private TextComponent componentForPlugin(PluginDescription description) {
         hoverText.append(Component.newline());
         if (description.getAuthors().size() == 1) {
           hoverText.append(Component.translatable("velocity.command.plugin-tooltip-author",
-              Component.text(description.getAuthors().get(0))));
+              Component.text(description.getAuthors().getFirst())));
         } else {
           hoverText.append(
               Component.translatable("velocity.command.plugin-tooltip-author",

proxy/src/main/java/com/velocitypowered/proxy/config/VelocityConfiguration.java

@@ -156,19 +156,16 @@ public boolean validate() {
     }
 
     switch (playerInfoForwardingMode) {
-      case NONE:
-        logger.warn("Player info forwarding is disabled! All players will appear to be connecting "
+      case NONE -> logger.warn("Player info forwarding is disabled! All players will appear to be connecting "
             + "from the proxy and will have offline-mode UUIDs.");
-        break;
-      case MODERN:
-      case BUNGEEGUARD:
+      case MODERN, BUNGEEGUARD -> {
         if (forwardingSecret == null || forwardingSecret.length == 0) {
           logger.error("You don't have a forwarding secret set. This is required for security.");
           valid = false;
         }
-        break;
-      default:
-        break;
+      }
+      default -> {
+      }
     }
 
     if (servers.getServers().isEmpty()) {

proxy/src/main/java/com/velocitypowered/proxy/connection/MinecraftConnection.java

@@ -153,13 +153,13 @@ public void channelRead(ChannelHandlerContext ctx, Object msg) throws Exception
 
       if (msg instanceof MinecraftPacket pkt) {
         if (!pkt.handle(activeSessionHandler)) {
-          activeSessionHandler.handleGeneric((MinecraftPacket) msg);
+          activeSessionHandler.handleGeneric(pkt);
         }
       } else if (msg instanceof HAProxyMessage proxyMessage) {
         this.remoteAddress = new InetSocketAddress(proxyMessage.sourceAddress(),
             proxyMessage.sourcePort());
-      } else if (msg instanceof ByteBuf) {
-        activeSessionHandler.handleUnknown((ByteBuf) msg);
+      } else if (msg instanceof ByteBuf buf) {
+        activeSessionHandler.handleUnknown(buf);
       }
     } finally {
       ReferenceCountUtil.release(msg);

proxy/src/main/java/com/velocitypowered/proxy/connection/backend/BackendPlaySessionHandler.java

@@ -452,8 +452,8 @@ public boolean handle(ClientboundCookieRequestPacket packet) {
 
   @Override
   public void handleGeneric(MinecraftPacket packet) {
-    if (packet instanceof PluginMessagePacket) {
-      ((PluginMessagePacket) packet).retain();
+    if (packet instanceof PluginMessagePacket pluginMessage) {
+      pluginMessage.retain();
     }
     playerConnection.delayedWrite(packet);
     if (++packetsFlushed >= MAXIMUM_PACKETS_TO_FLUSH) {

proxy/src/main/java/com/velocitypowered/proxy/connection/backend/BungeeCordMessageResponder.java

@@ -344,66 +344,30 @@ boolean process(PluginMessagePacket message) {
       return false;
     }
 
-    ByteBufDataInput in = new ByteBufDataInput(message.content());
-    String subChannel = in.readUTF();
+    final ByteBufDataInput in = new ByteBufDataInput(message.content());
+    final String subChannel = in.readUTF();
     switch (subChannel) {
-      case "GetPlayerServer":
-        this.processGetPlayerServer(in);
-        break;
-      case "ForwardToPlayer":
-        this.processForwardToPlayer(in);
-        break;
-      case "Forward":
-        this.processForwardToServer(in);
-        break;
-      case "Connect":
-        this.processConnect(in);
-        break;
-      case "ConnectOther":
-        this.processConnectOther(in);
-        break;
-      case "IP":
-        this.processIp(in);
-        break;
-      case "PlayerCount":
-        this.processPlayerCount(in);
-        break;
-      case "PlayerList":
-        this.processPlayerList(in);
-        break;
-      case "GetServers":
-        this.processGetServers();
-        break;
-      case "Message":
-        this.processMessage(in);
-        break;
-      case "MessageRaw":
-        this.processMessageRaw(in);
-        break;
-      case "GetServer":
-        this.processGetServer();
-        break;
-      case "UUID":
-        this.processUuid();
-        break;
-      case "UUIDOther":
-        this.processUuidOther(in);
-        break;
-      case "IPOther":
-        this.processIpOther(in);
-        break;
-      case "ServerIP":
-        this.processServerIp(in);
-        break;
-      case "KickPlayer":
-        this.processKick(in);
-        break;
-      case "KickPlayerRaw":
-        this.processKickRaw(in);
-        break;
-      default:
-        // Do nothing, unknown command
-        break;
+      case "GetPlayerServer" -> this.processGetPlayerServer(in);
+      case "ForwardToPlayer" -> this.processForwardToPlayer(in);
+      case "Forward" -> this.processForwardToServer(in);
+      case "Connect" -> this.processConnect(in);
+      case "ConnectOther" -> this.processConnectOther(in);
+      case "IP" -> this.processIp(in);
+      case "PlayerCount" -> this.processPlayerCount(in);
+      case "PlayerList" -> this.processPlayerList(in);
+      case "GetServers" -> this.processGetServers();
+      case "Message" -> this.processMessage(in);
+      case "MessageRaw" -> this.processMessageRaw(in);
+      case "GetServer" -> this.processGetServer();
+      case "UUID" -> this.processUuid();
+      case "UUIDOther" -> this.processUuidOther(in);
+      case "IPOther" -> this.processIpOther(in);
+      case "ServerIP" -> this.processServerIp(in);
+      case "KickPlayer" -> this.processKick(in);
+      case "KickPlayerRaw" -> this.processKickRaw(in);
+      default -> {
+          // Do nothing, unknown command
+      }
     }
 
     return true;

proxy/src/main/java/com/velocitypowered/proxy/connection/backend/TransitionSessionHandler.java

@@ -122,9 +122,8 @@ public boolean handle(JoinGamePacket packet) {
           // Change the client to use the ClientPlaySessionHandler if required.
           ClientPlaySessionHandler playHandler;
           if (player.getConnection()
-              .getActiveSessionHandler() instanceof ClientPlaySessionHandler) {
-            playHandler =
-                (ClientPlaySessionHandler) player.getConnection().getActiveSessionHandler();
+              .getActiveSessionHandler() instanceof ClientPlaySessionHandler sessionHandler) {
+            playHandler = sessionHandler;
           } else {
             playHandler = new ClientPlaySessionHandler(server, player);
             player.getConnection().setActiveSessionHandler(StateRegistry.PLAY, playHandler);

proxy/src/main/java/com/velocitypowered/proxy/connection/backend/VelocityServerConnection.java

@@ -180,9 +180,8 @@ private void startHandshake() {
       handshake.setServerAddress(createBungeeGuardForwardingAddress(secret));
     } else if (proxyPlayer.getConnection().getType() == ConnectionTypes.LEGACY_FORGE) {
       handshake.setServerAddress(playerVhost + HANDSHAKE_HOSTNAME_TOKEN);
-    } else if (proxyPlayer.getConnection().getType() instanceof ModernForgeConnectionType) {
-      handshake.setServerAddress(playerVhost + ((ModernForgeConnectionType) proxyPlayer
-              .getConnection().getType()).getModernToken());
+    } else if (proxyPlayer.getConnection().getType() instanceof ModernForgeConnectionType forgeConnection) {
+      handshake.setServerAddress(playerVhost + forgeConnection.getModernToken());
     } else {
       handshake.setServerAddress(playerVhost);
     }