I missed a spot

api/src/main/java/com/velocitypowered/api/event/player/GameProfileRequestEvent.java

@@ -7,53 +7,23 @@
 
 package com.velocitypowered.api.event.player;
 
-import com.google.common.base.Preconditions;
 import com.velocitypowered.api.proxy.connection.InboundConnection;
 import com.velocitypowered.api.util.GameProfile;
 import org.checkerframework.checker.nullness.qual.Nullable;
 
 /**
- * This event is fired after the {@link PreLoginEventImpl} in
- * order to set up the game profile for the user. This can be used to configure a custom profile for
- * a user, i.e. skin replacement.
+ * This event is fired after the {@link PreLoginEventImpl} in order to set up the game profile for
+ * the user. This can be used to configure a custom profile for a user, i.e. skin replacement.
  */
-public final class GameProfileRequestEvent {
+public interface GameProfileRequestEvent {
 
-  private final String username;
-  private final InboundConnection connection;
-  private final GameProfile originalProfile;
-  private final boolean onlineMode;
-  private @Nullable GameProfile gameProfile;
+  InboundConnection getConnection();
 
-  /**
-   * Creates a new instance.
-   * @param connection the connection connecting to the proxy
-   * @param originalProfile the original {@link GameProfile} for the user
-   * @param onlineMode whether or not the user connected in online or offline mode
-   */
-  public GameProfileRequestEvent(InboundConnection connection, GameProfile originalProfile,
-      boolean onlineMode) {
-    this.connection = Preconditions.checkNotNull(connection, "connection");
-    this.originalProfile = Preconditions.checkNotNull(originalProfile, "originalProfile");
-    this.username = originalProfile.getName();
-    this.onlineMode = onlineMode;
-  }
+  String getUsername();
 
-  public InboundConnection getConnection() {
-    return connection;
-  }
+  GameProfile getOriginalProfile();
 
-  public String getUsername() {
-    return username;
-  }
-
-  public GameProfile getOriginalProfile() {
-    return originalProfile;
-  }
-
-  public boolean isOnlineMode() {
-    return onlineMode;
-  }
+  boolean isOnlineMode();
 
   /**
    * Returns the game profile that will be used to initialize the connection with. Should no profile
@@ -62,26 +32,12 @@ public final class GameProfileRequestEvent {
    *
    * @return the user's {@link GameProfile}
    */
-  public GameProfile getGameProfile() {
-    return gameProfile == null ? originalProfile : gameProfile;
-  }
+  GameProfile getGameProfile();
 
   /**
    * Sets the game profile to use for this connection.
    *
    * @param gameProfile the profile for this connection, {@code null} uses the original profile
    */
-  public void setGameProfile(@Nullable GameProfile gameProfile) {
-    this.gameProfile = gameProfile;
-  }
-
-  @Override
-  public String toString() {
-    return "GameProfileRequestEvent{"
-        + "username=" + username
-        + ", gameProfile=" + gameProfile
-        + "}";
-  }
-
-
+  void setGameProfile(@Nullable GameProfile gameProfile);
 }

api/src/main/java/com/velocitypowered/api/event/player/GameProfileRequestEventImpl.java

@@ -0,0 +1,92 @@
+/*
+ * Copyright (C) 2018 Velocity Contributors
+ *
+ * The Velocity API is licensed under the terms of the MIT License. For more details,
+ * reference the LICENSE file in the api top-level directory.
+ */
+
+package com.velocitypowered.api.event.player;
+
+import com.google.common.base.Preconditions;
+import com.velocitypowered.api.proxy.connection.InboundConnection;
+import com.velocitypowered.api.util.GameProfile;
+import org.checkerframework.checker.nullness.qual.Nullable;
+
+/**
+ * This event is fired after the {@link PreLoginEventImpl} in order to set up the game profile for
+ * the user. This can be used to configure a custom profile for a user, i.e. skin replacement.
+ */
+public final class GameProfileRequestEventImpl implements GameProfileRequestEvent {
+
+  private final String username;
+  private final InboundConnection connection;
+  private final GameProfile originalProfile;
+  private final boolean onlineMode;
+  private @Nullable GameProfile gameProfile;
+
+  /**
+   * Creates a new instance.
+   * @param connection the connection connecting to the proxy
+   * @param originalProfile the original {@link GameProfile} for the user
+   * @param onlineMode whether or not the user connected in online or offline mode
+   */
+  public GameProfileRequestEventImpl(InboundConnection connection, GameProfile originalProfile,
+      boolean onlineMode) {
+    this.connection = Preconditions.checkNotNull(connection, "connection");
+    this.originalProfile = Preconditions.checkNotNull(originalProfile, "originalProfile");
+    this.username = originalProfile.getName();
+    this.onlineMode = onlineMode;
+  }
+
+  @Override
+  public InboundConnection getConnection() {
+    return connection;
+  }
+
+  @Override
+  public String getUsername() {
+    return username;
+  }
+
+  @Override
+  public GameProfile getOriginalProfile() {
+    return originalProfile;
+  }
+
+  @Override
+  public boolean isOnlineMode() {
+    return onlineMode;
+  }
+
+  /**
+   * Returns the game profile that will be used to initialize the connection with. Should no profile
+   * be currently specified, the one generated by the proxy (for offline mode) or retrieved from the
+   * Mojang session servers (for online mode) will be returned instead.
+   *
+   * @return the user's {@link GameProfile}
+   */
+  @Override
+  public GameProfile getGameProfile() {
+    return gameProfile == null ? originalProfile : gameProfile;
+  }
+
+  /**
+   * Sets the game profile to use for this connection.
+   *
+   * @param gameProfile the profile for this connection, {@code null} uses the original profile
+   */
+  @Override
+  public void setGameProfile(@Nullable GameProfile gameProfile) {
+    this.gameProfile = gameProfile;
+  }
+
+  @Override
+  public String toString() {
+    return "GameProfileRequestEvent{"
+        + "username=" + username
+        + ", gameProfile=" + gameProfile
+        + "}";
+  }
+
+
+}

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

@@ -29,6 +29,7 @@ import com.velocitypowered.api.event.permission.PermissionsSetupEventImpl;
 import com.velocitypowered.api.event.player.DisconnectEvent.LoginStatus;
 import com.velocitypowered.api.event.player.DisconnectEventImpl;
 import com.velocitypowered.api.event.player.GameProfileRequestEvent;
+import com.velocitypowered.api.event.player.GameProfileRequestEventImpl;
 import com.velocitypowered.api.event.player.LoginEventImpl;
 import com.velocitypowered.api.event.player.PlayerChooseInitialServerEvent;
 import com.velocitypowered.api.event.player.PlayerChooseInitialServerEventImpl;
@@ -225,7 +226,7 @@ public class LoginSessionHandler implements MinecraftSessionHandler {
     // Some connection types may need to alter the game profile.
     profile = mcConnection.getType().addGameProfileTokensIfRequired(profile,
         server.getConfiguration().getPlayerInfoForwardingMode());
-    GameProfileRequestEvent profileRequestEvent = new GameProfileRequestEvent(inbound, profile,
+    GameProfileRequestEvent profileRequestEvent = new GameProfileRequestEventImpl(inbound, profile,
         onlineMode);
     final GameProfile finalProfile = profile;