Allow fallback to other server connections in the event of an exception.

Also removes some debugging code.

proxy/src/main/java/com/velocitypowered/proxy/VelocityServer.java

@@ -8,7 +8,6 @@ import com.google.gson.GsonBuilder;
 import com.velocitypowered.api.event.EventManager;
 import com.velocitypowered.api.event.proxy.ProxyInitializeEvent;
 import com.velocitypowered.api.event.proxy.ProxyReloadEvent;
-import com.velocitypowered.api.event.proxy.ProxyShutdownEvent;
 import com.velocitypowered.api.plugin.PluginContainer;
 import com.velocitypowered.api.plugin.PluginManager;
 import com.velocitypowered.api.proxy.Player;
@@ -50,7 +49,6 @@ import java.nio.file.Paths;
 import java.security.KeyPair;
 import java.util.ArrayList;
 import java.util.Collection;
-import java.util.Collections;
 import java.util.Locale;
 import java.util.Map;
 import java.util.Objects;

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

@@ -31,6 +31,7 @@ public class BackendPlaySessionHandler implements MinecraftSessionHandler {
   private final VelocityServer server;
   private final VelocityServerConnection serverConn;
   private final ClientPlaySessionHandler playerSessionHandler;
+  private boolean exceptionTriggered = false;
 
   BackendPlaySessionHandler(VelocityServer server, VelocityServerConnection serverConn) {
     this.server = server;
@@ -167,6 +168,7 @@ public class BackendPlaySessionHandler implements MinecraftSessionHandler {
 
   @Override
   public void exception(Throwable throwable) {
+    exceptionTriggered = true;
     serverConn.getPlayer().handleConnectionException(serverConn.getServer(), throwable);
   }
 
@@ -177,7 +179,7 @@ public class BackendPlaySessionHandler implements MinecraftSessionHandler {
   @Override
   public void disconnected() {
     serverConn.getServer().removePlayer(serverConn.getPlayer());
-    if (!serverConn.isGracefulDisconnect()) {
+    if (!serverConn.isGracefulDisconnect() && !exceptionTriggered) {
       serverConn.getPlayer().disconnect(ConnectionMessages.UNEXPECTED_DISCONNECT);
     }
   }

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

@@ -667,8 +667,6 @@ public class ConnectedPlayer implements MinecraftConnectionAssociation, Player {
               return;
             }
 
-            System.out.println(status);
-
             switch (status.getStatus()) {
               case ALREADY_CONNECTED:
                 sendMessage(ConnectionMessages.ALREADY_CONNECTED);