More Checkstyle.

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

@@ -104,8 +104,7 @@ public class VelocityCommand implements Command {
           .build();
       TextComponent copyright = TextComponent
           .of("Copyright 2018 " + version.getVendor() + ". " + version.getName()
-              + " is freely licensed under the terms of the " +
-              "MIT License.");
+              + " is freely licensed under the terms of the MIT License.");
       source.sendMessage(velocity);
       source.sendMessage(copyright);
 

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

@@ -20,7 +20,7 @@ import org.apache.logging.log4j.LogManager;
 import org.apache.logging.log4j.Logger;
 
 /**
- * Simple annotation and fields based TOML configuration serializer
+ * Simple annotation and fields based TOML configuration serializer.
  */
 public abstract class AnnotatedConfig {
 
@@ -31,7 +31,7 @@ public abstract class AnnotatedConfig {
   }
 
   /**
-   * Indicates that a field is a table
+   * Indicates that a field is a table.
    */
   @Retention(RetentionPolicy.RUNTIME)
   @Target({ElementType.FIELD, ElementType.TYPE})
@@ -41,7 +41,7 @@ public abstract class AnnotatedConfig {
   }
 
   /**
-   * Creates a comment
+   * Creates a comment.
    */
   @Retention(RetentionPolicy.RUNTIME)
   @Target({ElementType.FIELD, ElementType.TYPE})
@@ -51,7 +51,7 @@ public abstract class AnnotatedConfig {
   }
 
   /**
-   * How field will be named in config
+   * How field will be named in config.
    */
   @Retention(RetentionPolicy.RUNTIME)
   @Target({ElementType.FIELD, ElementType.TYPE})
@@ -61,7 +61,7 @@ public abstract class AnnotatedConfig {
   }
 
   /**
-   * Indicates that a field is a map and we need to save all map data to config
+   * Indicates that a field is a map and we need to save all map data to config.
    */
   @Retention(RetentionPolicy.RUNTIME)
   @Target({ElementType.FIELD, ElementType.TYPE})
@@ -70,7 +70,7 @@ public abstract class AnnotatedConfig {
   }
 
   /**
-   * Indicates that a field is a string converted to byte[]
+   * Indicates that a field is a string converted to byte[].
    */
   @Retention(RetentionPolicy.RUNTIME)
   @Target({ElementType.FIELD, ElementType.TYPE})
@@ -79,7 +79,7 @@ public abstract class AnnotatedConfig {
   }
 
   /**
-   * Indicates that a field should be skipped
+   * Indicates that a field should be skipped.
    */
   @Retention(RetentionPolicy.RUNTIME)
   @Target({ElementType.FIELD})
@@ -88,7 +88,7 @@ public abstract class AnnotatedConfig {
   }
 
   /**
-   * Dumps this configuration to list of strings using {@link #dumpConfig(Object)}
+   * Dumps this configuration to list of strings using {@link #dumpConfig(Object)}.
    *
    * @return configuration dump
    */
@@ -123,22 +123,23 @@ public abstract class AnnotatedConfig {
           }
         }
 
-        // Get a key name for config
+        // Get a key name for config. Use field name if @ConfigKey annotation is not present.
         ConfigKey key = field.getAnnotation(ConfigKey.class);
-        String name = safeKey(key == null ? field.getName()
-            : key.value()); // Use field name if @ConfigKey annotation is not present
+        final String name = safeKey(key == null ? field.getName() : key.value());
+
+        Object value = field.get(dumpable);
 
         // Check if field is table.
         Table table = field.getAnnotation(Table.class);
         if (table != null) {
           lines.add(table.value()); // Write [name]
-          lines.addAll(dumpConfig(field.get(dumpable))); // Dump fields of table
+          lines.addAll(dumpConfig(value)); // Dump fields of table
           continue;
         }
 
         if (field.getAnnotation(IsMap.class) != null) { // Check if field is a map
           @SuppressWarnings("unchecked")
-          Map<String, ?> map = (Map<String, ?>) field.get(dumpable);
+          Map<String, ?> map = (Map<String, ?>) value;
           for (Entry<String, ?> entry : map.entrySet()) {
             lines.add(
                 safeKey(entry.getKey()) + " = " + serialize(entry.getValue())); // Save map data
@@ -147,8 +148,6 @@ public abstract class AnnotatedConfig {
           continue;
         }
 
-        Object value = field.get(dumpable);
-
         // Check if field is a byte[] representation of a string
         if (field.getAnnotation(StringAsBytes.class) != null) {
           value = new String((byte[]) value, StandardCharsets.UTF_8);

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

@@ -522,9 +522,9 @@ public class VelocityConfiguration extends AnnotatedConfig implements ProxyConfi
 
     @Override
     public String toString() {
-      return "ForcedHosts{" +
-          "forcedHosts=" + forcedHosts +
-          '}';
+      return "ForcedHosts{"
+          + "forcedHosts=" + forcedHosts
+          + '}';
     }
   }
 
@@ -601,14 +601,14 @@ public class VelocityConfiguration extends AnnotatedConfig implements ProxyConfi
 
     @Override
     public String toString() {
-      return "Advanced{" +
-          "compressionThreshold=" + compressionThreshold +
-          ", compressionLevel=" + compressionLevel +
-          ", loginRatelimit=" + loginRatelimit +
-          ", connectionTimeout=" + connectionTimeout +
-          ", readTimeout=" + readTimeout +
-          ", proxyProtocol=" + proxyProtocol +
-          '}';
+      return "Advanced{"
+          + "compressionThreshold=" + compressionThreshold
+          + ", compressionLevel=" + compressionLevel
+          + ", loginRatelimit=" + loginRatelimit
+          + ", connectionTimeout=" + connectionTimeout
+          + ", readTimeout=" + readTimeout
+          + ", proxyProtocol=" + proxyProtocol
+          + '}';
     }
   }
 
@@ -667,12 +667,12 @@ public class VelocityConfiguration extends AnnotatedConfig implements ProxyConfi
 
     @Override
     public String toString() {
-      return "Query{" +
-          "queryEnabled=" + queryEnabled +
-          ", queryPort=" + queryPort +
-          ", queryMap='" + queryMap + '\'' +
-          ", showPlugins=" + showPlugins +
-          '}';
+      return "Query{"
+          + "queryEnabled=" + queryEnabled
+          + ", queryPort=" + queryPort
+          + ", queryMap='" + queryMap + '\''
+          + ", showPlugins=" + showPlugins
+          + '}';
     }
   }
 }

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

@@ -58,7 +58,7 @@ public class MinecraftConnection extends ChannelInboundHandlerAdapter {
   private @Nullable MinecraftConnectionAssociation association;
   private boolean isLegacyForge;
   private final VelocityServer server;
-  private boolean canSendLegacyFMLResetPacket = false;
+  private boolean canSendLegacyFmlResetPacket = false;
 
   public MinecraftConnection(Channel channel, VelocityServer server) {
     this.channel = channel;
@@ -287,12 +287,12 @@ public class MinecraftConnection extends ChannelInboundHandlerAdapter {
     this.isLegacyForge = isForge;
   }
 
-  public boolean canSendLegacyFMLResetPacket() {
-    return canSendLegacyFMLResetPacket;
+  public boolean canSendLegacyFmlResetPacket() {
+    return canSendLegacyFmlResetPacket;
   }
 
-  public void setCanSendLegacyFMLResetPacket(boolean canSendLegacyFMLResetPacket) {
-    this.canSendLegacyFMLResetPacket = isLegacyForge && canSendLegacyFMLResetPacket;
+  public void setCanSendLegacyFmlResetPacket(boolean canSendLegacyFMLResetPacket) {
+    this.canSendLegacyFmlResetPacket = isLegacyForge && canSendLegacyFMLResetPacket;
   }
 
   public int getNextProtocolVersion() {

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

@@ -173,16 +173,16 @@ public class BackendPlaySessionHandler implements MinecraftSessionHandler {
     if (mc == null) {
       return false;
     }
-    boolean isMCOrFMLMessage;
+    boolean minecraftOrFmlMessage;
     if (mc.getProtocolVersion() <= ProtocolConstants.MINECRAFT_1_12_2) {
       String channel = message.getChannel();
-      isMCOrFMLMessage = channel.startsWith("MC|") || channel
+      minecraftOrFmlMessage = channel.startsWith("MC|") || channel
           .startsWith(ForgeConstants.FORGE_LEGACY_HANDSHAKE_CHANNEL);
     } else {
-      isMCOrFMLMessage = message.getChannel().startsWith("minecraft:");
+      minecraftOrFmlMessage = message.getChannel().startsWith("minecraft:");
     }
-    return isMCOrFMLMessage || playerSessionHandler.getClientPluginMsgChannels()
-        .contains(message.getChannel()) ||
-        server.getChannelRegistrar().registered(message.getChannel());
+    return minecraftOrFmlMessage
+        || playerSessionHandler.getKnownChannels().contains(message.getChannel())
+        || server.getChannelRegistrar().registered(message.getChannel());
   }
 }

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

@@ -32,6 +32,9 @@ import net.kyori.text.TextComponent;
 
 public class LoginSessionHandler implements MinecraftSessionHandler {
 
+  private static final TextComponent MODERN_IP_FORWARDING_FAILURE = TextComponent
+      .of("Your server did not send a forwarding request to the proxy. Is it set up correctly?");
+
   private final VelocityServer server;
   private final VelocityServerConnection serverConn;
   private final CompletableFuture<ConnectionRequestBuilder.Result> resultFuture;
@@ -100,9 +103,7 @@ public class LoginSessionHandler implements MinecraftSessionHandler {
   public boolean handle(ServerLoginSuccess packet) {
     if (server.getConfiguration().getPlayerInfoForwardingMode() == PlayerInfoForwarding.MODERN
         && !informationForwarded) {
-      resultFuture.complete(ConnectionRequestResults.forDisconnect(
-          TextComponent
-              .of("Your server did not send a forwarding request to the proxy. Is it set up correctly?")));
+      resultFuture.complete(ConnectionRequestResults.forDisconnect(MODERN_IP_FORWARDING_FAILURE));
       serverConn.disconnect();
       return true;
     }

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

@@ -198,7 +198,7 @@ public class VelocityServerConnection implements MinecraftConnectionAssociation,
     return legacyForge;
   }
 
-  public void setLegacyForge(boolean modded) {
+  void setLegacyForge(boolean modded) {
     legacyForge = modded;
   }
 
@@ -210,7 +210,7 @@ public class VelocityServerConnection implements MinecraftConnectionAssociation,
     this.hasCompletedJoin = hasCompletedJoin;
   }
 
-  public boolean isGracefulDisconnect() {
+  boolean isGracefulDisconnect() {
     return gracefulDisconnect;
   }
 
@@ -222,7 +222,7 @@ public class VelocityServerConnection implements MinecraftConnectionAssociation,
     return lastPingSent;
   }
 
-  public void setLastPingId(long lastPingId) {
+  void setLastPingId(long lastPingId) {
     this.lastPingId = lastPingId;
     this.lastPingSent = System.currentTimeMillis();
   }

proxy/src/main/java/com/velocitypowered/proxy/connection/client/ClientPlaySessionHandler.java

@@ -52,7 +52,7 @@ public class ClientPlaySessionHandler implements MinecraftSessionHandler {
   private final ConnectedPlayer player;
   private boolean spawned = false;
   private final List<UUID> serverBossBars = new ArrayList<>();
-  private final Set<String> clientPluginMsgChannels = new HashSet<>();
+  private final Set<String> knownChannels = new HashSet<>();
   private final Queue<PluginMessage> loginPluginMessages = new ArrayDeque<>();
   private final VelocityServer server;
   private @Nullable TabCompleteRequest outstandingTabComplete;
@@ -163,11 +163,11 @@ public class ClientPlaySessionHandler implements MinecraftSessionHandler {
         List<String> actuallyRegistered = new ArrayList<>();
         List<String> channels = PluginMessageUtil.getChannels(packet);
         for (String channel : channels) {
-          if (clientPluginMsgChannels.size() >= MAX_PLUGIN_CHANNELS &&
-              !clientPluginMsgChannels.contains(channel)) {
+          if (knownChannels.size() >= MAX_PLUGIN_CHANNELS &&
+              !knownChannels.contains(channel)) {
             throw new IllegalStateException("Too many plugin message channels registered");
           }
-          if (clientPluginMsgChannels.add(channel)) {
+          if (knownChannels.add(channel)) {
             actuallyRegistered.add(channel);
           }
         }
@@ -179,7 +179,7 @@ public class ClientPlaySessionHandler implements MinecraftSessionHandler {
         }
       } else if (PluginMessageUtil.isMCUnregister(packet)) {
         List<String> channels = PluginMessageUtil.getChannels(packet);
-        clientPluginMsgChannels.removeAll(channels);
+        knownChannels.removeAll(channels);
         backendConn.write(packet);
       } else if (PluginMessageUtil.isMCBrand(packet)) {
         backendConn.write(PluginMessageUtil.rewriteMinecraftBrand(packet));
@@ -296,7 +296,7 @@ public class ClientPlaySessionHandler implements MinecraftSessionHandler {
       // Forge client that we must reset on the next switch.
       //
       // The call will handle if the player is not a Forge player appropriately.
-      player.getConnection().setCanSendLegacyFMLResetPacket(true);
+      player.getConnection().setCanSendLegacyFmlResetPacket(true);
     } else {
       // Clear tab list to avoid duplicate entries
       player.getTabList().clearAll();
@@ -334,7 +334,7 @@ public class ClientPlaySessionHandler implements MinecraftSessionHandler {
 
     // Tell the server about this client's plugin message channels.
     int serverVersion = serverMc.getProtocolVersion();
-    Collection<String> toRegister = new HashSet<>(clientPluginMsgChannels);
+    Collection<String> toRegister = new HashSet<>(knownChannels);
     if (serverVersion >= ProtocolConstants.MINECRAFT_1_13) {
       toRegister.addAll(server.getChannelRegistrar().getModernChannelIds());
     } else {
@@ -370,7 +370,7 @@ public class ClientPlaySessionHandler implements MinecraftSessionHandler {
       // don't want to set it false if this is a first connection to a Vanilla server.
       //
       // See LoginSessionHandler#handle for where the counterpart to this method is
-      player.getConnection().setCanSendLegacyFMLResetPacket(true);
+      player.getConnection().setCanSendLegacyFmlResetPacket(true);
     }
   }
 
@@ -378,8 +378,8 @@ public class ClientPlaySessionHandler implements MinecraftSessionHandler {
     return serverBossBars;
   }
 
-  public Set<String> getClientPluginMsgChannels() {
-    return clientPluginMsgChannels;
+  public Set<String> getKnownChannels() {
+    return knownChannels;
   }
 
   public void handleTabCompleteResponse(TabCompleteResponse response) {

proxy/src/main/java/com/velocitypowered/proxy/connection/client/ConnectedPlayer.java

@@ -450,9 +450,9 @@ public class ConnectedPlayer implements MinecraftConnectionAssociation, Player {
   }
 
   public void sendLegacyForgeHandshakeResetPacket() {
-    if (connection.canSendLegacyFMLResetPacket()) {
+    if (connection.canSendLegacyFmlResetPacket()) {
       connection.write(ForgeConstants.resetPacket());
-      connection.setCanSendLegacyFMLResetPacket(false);
+      connection.setCanSendLegacyFmlResetPacket(false);
     }
   }
 

proxy/src/main/java/com/velocitypowered/proxy/plugin/util/PluginDependencyUtils.java

@@ -15,7 +15,6 @@ import java.util.List;
 import java.util.Map;
 import java.util.Queue;
 import java.util.Set;
-import org.checkerframework.checker.nullness.qual.NonNull;
 
 public class PluginDependencyUtils {
 
@@ -23,8 +22,15 @@ public class PluginDependencyUtils {
     throw new AssertionError();
   }
 
-  public static List<PluginDescription> sortCandidates(
-      List<@NonNull PluginDescription> candidates) {
+  /**
+   * Attempts to topographically sort all plugins for the proxy to load by dependencies using
+   * Kahn's algorithm.
+   *
+   * @param candidates the plugins to sort
+   * @return the sorted list of plugins
+   * @throws IllegalStateException if there is a circular loop in the dependency graph
+   */
+  public static List<PluginDescription> sortCandidates(List<PluginDescription> candidates) {
     // Create our graph, we're going to be using this for Kahn's algorithm.
     MutableGraph<PluginDescription> graph = GraphBuilder.directed().allowsSelfLoops(false).build();
     Map<String, PluginDescription> candidateMap = Maps
@@ -69,7 +75,7 @@ public class PluginDependencyUtils {
     return sorted;
   }
 
-  public static Queue<PluginDescription> getNoDependencyCandidates(Graph<PluginDescription> graph) {
+  private static Queue<PluginDescription> getNoDependencyCandidates(Graph<PluginDescription> graph) {
     Queue<PluginDescription> found = new ArrayDeque<>();
 
     for (PluginDescription node : graph.nodes()) {
@@ -81,7 +87,7 @@ public class PluginDependencyUtils {
     return found;
   }
 
-  public static String createLoopInformation(Graph<PluginDescription> graph) {
+  private static String createLoopInformation(Graph<PluginDescription> graph) {
     StringBuilder repr = new StringBuilder("{");
     for (EndpointPair<PluginDescription> edge : graph.edges()) {
       repr.append(edge.target().getId()).append(": [");

proxy/src/main/java/com/velocitypowered/proxy/protocol/StateRegistry.java

@@ -190,10 +190,8 @@ public enum StateRegistry {
 
   public static final int STATUS_ID = 1;
   public static final int LOGIN_ID = 2;
-  public final PacketRegistry CLIENTBOUND = new PacketRegistry(
-      ProtocolConstants.Direction.CLIENTBOUND);
-  public final PacketRegistry SERVERBOUND = new PacketRegistry(
-      ProtocolConstants.Direction.SERVERBOUND);
+  public final PacketRegistry CLIENTBOUND = new PacketRegistry(Direction.CLIENTBOUND);
+  public final PacketRegistry SERVERBOUND = new PacketRegistry(Direction.SERVERBOUND);
 
   public static class PacketRegistry {
 
@@ -210,11 +208,11 @@ public enum StateRegistry {
           .put(MINECRAFT_1_13, ImmutableIntArray.of(MINECRAFT_1_13_1, MINECRAFT_1_13_2));
     }
 
-    private final ProtocolConstants.Direction direction;
+    private final Direction direction;
     private final IntObjectMap<ProtocolVersion> versions = new IntObjectHashMap<>(16);
     private boolean fallback = true;
 
-    public PacketRegistry(Direction direction) {
+    PacketRegistry(Direction direction) {
       this.direction = direction;
       ProtocolConstants.SUPPORTED_VERSIONS
           .forEach(version -> versions.put(version, new ProtocolVersion(version)));
@@ -267,10 +265,10 @@ public enum StateRegistry {
     public class ProtocolVersion {
 
       public final int version;
-      final IntObjectMap<Supplier<? extends MinecraftPacket>> packetIdToSupplier = new IntObjectHashMap<>(
-          16, 0.5f);
-      final Object2IntMap<Class<? extends MinecraftPacket>> packetClassToId = new Object2IntOpenHashMap<>(
-          16, 0.5f);
+      final IntObjectMap<Supplier<? extends MinecraftPacket>> packetIdToSupplier =
+          new IntObjectHashMap<>(16, 0.5f);
+      final Object2IntMap<Class<? extends MinecraftPacket>> packetClassToId =
+          new Object2IntOpenHashMap<>(16, 0.5f);
 
       ProtocolVersion(final int version) {
         this.version = version;
@@ -312,11 +310,11 @@ public enum StateRegistry {
 
     @Override
     public String toString() {
-      return "PacketMapping{" +
-          "id=" + id +
-          ", protocolVersion=" + protocolVersion +
-          ", encodeOnly=" + encodeOnly +
-          '}';
+      return "PacketMapping{"
+          + "id=" + id
+          + ", protocolVersion=" + protocolVersion
+          + ", encodeOnly=" + encodeOnly
+          + '}';
     }
 
     @Override
@@ -328,9 +326,9 @@ public enum StateRegistry {
         return false;
       }
       PacketMapping that = (PacketMapping) o;
-      return id == that.id &&
-          protocolVersion == that.protocolVersion &&
-          encodeOnly == that.encodeOnly;
+      return id == that.id
+          && protocolVersion == that.protocolVersion
+          && encodeOnly == that.encodeOnly;
     }
 
     @Override
@@ -340,7 +338,7 @@ public enum StateRegistry {
   }
 
   /**
-   * Creates a PacketMapping using the provided arguments
+   * Creates a PacketMapping using the provided arguments.
    *
    * @param id Packet Id
    * @param version Protocol version

proxy/src/main/java/com/velocitypowered/proxy/protocol/netty/MinecraftCompressDecoder.java

@@ -31,8 +31,8 @@ public class MinecraftCompressDecoder extends MessageToMessageDecoder<ByteBuf> {
     }
 
     Preconditions.checkState(uncompressedSize >= threshold,
-        "Uncompressed size %s doesn't make sense with threshold %s", uncompressedSize, threshold);
-    // Try to use the uncompressed size, but place a cap if it might be too big (possibly malicious).
+        "Uncompressed size %s is greater than threshold %s",
+        uncompressedSize, threshold);
     ByteBuf uncompressed = ctx.alloc()
         .buffer(Math.min(uncompressedSize, MAXIMUM_INITIAL_BUFFER_SIZE));
     try {
@@ -41,7 +41,6 @@ public class MinecraftCompressDecoder extends MessageToMessageDecoder<ByteBuf> {
           "Mismatched compression sizes");
       out.add(uncompressed);
     } catch (Exception e) {
-      // If something went wrong, rethrow the exception, but ensure we free our temporary buffer first.
       uncompressed.release();
       throw e;
     }

proxy/src/test/java/com/velocitypowered/proxy/testutil/FakePluginManager.java

@@ -14,8 +14,8 @@ public class FakePluginManager implements PluginManager {
   public static final Object PLUGIN_A = new Object();
   public static final Object PLUGIN_B = new Object();
 
-  public static final PluginContainer PC_A = new FakePluginContainer("a", PLUGIN_A);
-  public static final PluginContainer PC_B = new FakePluginContainer("b", PLUGIN_B);
+  private static final PluginContainer PC_A = new FakePluginContainer("a", PLUGIN_A);
+  private static final PluginContainer PC_B = new FakePluginContainer("b", PLUGIN_B);
 
   @Override
   public @NonNull Optional<PluginContainer> fromInstance(@NonNull Object instance) {