Fix issues with server connections.

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

@@ -4,8 +4,10 @@ import com.google.common.base.Preconditions;
 import com.velocitypowered.api.event.ResultedEvent;
 import com.velocitypowered.api.proxy.Player;
 import com.velocitypowered.api.proxy.server.RegisteredServer;
+import java.util.Optional;
 import net.kyori.text.Component;
 import org.checkerframework.checker.nullness.qual.NonNull;
+import org.checkerframework.checker.nullness.qual.Nullable;
 
 /**
  * Fired when a player is kicked from a server. You may either allow Velocity to kick the player
@@ -16,15 +18,15 @@ public final class KickedFromServerEvent implements
 
   private final Player player;
   private final RegisteredServer server;
-  private final Component originalReason;
+  private final @Nullable Component originalReason;
   private final boolean duringServerConnect;
   private ServerKickResult result;
 
-  public KickedFromServerEvent(Player player, RegisteredServer server, Component originalReason,
+  public KickedFromServerEvent(Player player, RegisteredServer server,
-      boolean duringServerConnect, Component fancyReason) {
+      @Nullable Component originalReason, boolean duringServerConnect, Component fancyReason) {
     this.player = Preconditions.checkNotNull(player, "player");
     this.server = Preconditions.checkNotNull(server, "server");
-    this.originalReason = Preconditions.checkNotNull(originalReason, "originalReason");
+    this.originalReason = originalReason;
     this.duringServerConnect = duringServerConnect;
     this.result = new Notify(fancyReason);
   }
@@ -47,8 +49,8 @@ public final class KickedFromServerEvent implements
     return server;
   }
 
-  public Component getOriginalReason() {
+  public Optional<Component> getOriginalReason() {
-    return originalReason;
+    return Optional.ofNullable(originalReason);
   }
 
   /**

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

@@ -324,7 +324,8 @@ public class ClientPlaySessionHandler implements MinecraftSessionHandler {
               joinGame.getLevelType()));
     }
 
-    // Remove old boss bars. These don't get cleared when sending JoinGame so we need to track these.
+    // Remove previous boss bars. These don't get cleared when sending JoinGame, thus the need to
+    // track them.
     for (UUID serverBossBar : serverBossBars) {
       BossBar deletePacket = new BossBar();
       deletePacket.setUuid(serverBossBar);

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

@@ -350,11 +350,9 @@ public class ConnectedPlayer implements MinecraftConnectionAssociation, Player {
       } else {
         connection.closeWith(Disconnect.create(friendlyReason));
       }
-    } else if (kickReason != null) {
+    } else {
-      // Already connected to the server being disconnected from.
       KickedFromServerEvent originalEvent = new KickedFromServerEvent(this, rs, kickReason,
           !connectedServer.getServer().equals(rs), friendlyReason);
-
       server.getEventManager().fire(originalEvent)
           .thenAcceptAsync(event -> {
             if (event.getResult() instanceof DisconnectPlayer) {
@@ -375,8 +373,6 @@ public class ConnectedPlayer implements MinecraftConnectionAssociation, Player {
               connection.closeWith(Disconnect.create(friendlyReason));
             }
           }, connection.eventLoop());
-    } else {
-      connection.closeWith(Disconnect.create(friendlyReason));
     }
   }