Prevent shutdown error deadlocks

SpigotCore_Main/src/de/steamwar/core/Core.java

@@ -56,6 +56,8 @@ public class Core extends JavaPlugin{
 			version = 12;
 	}
 
+	private ErrorHandler errorHandler;
+
 	@Override
 	public void onLoad() {
 		setInstance(this);
@@ -63,7 +65,7 @@ public class Core extends JavaPlugin{
 	
 	@Override
 	public void onEnable() {
-		new ErrorHandler();
+		errorHandler = new ErrorHandler();
 
 		Bukkit.getPluginManager().registerEvents(new PlayerJoinedEvent(), this);
 		Bukkit.getPluginManager().registerEvents(new ChattingEvent(), this);
@@ -81,6 +83,7 @@ public class Core extends JavaPlugin{
 
 	@Override
 	public void onDisable() {
+		errorHandler.unregister();
 		SQL.close();
 	}
 

SpigotCore_Main/src/de/steamwar/core/ErrorHandler.java

@@ -39,6 +39,10 @@ public class ErrorHandler extends Handler {
         Logger.getLogger("").addHandler(this);
     }
 
+    void unregister() {
+        Logger.getLogger("").removeHandler(this);
+    }
+
     @Override
     public void publish(LogRecord logRecord) {
         if(logRecord.getLevel().intValue() < Level.WARNING.intValue())