NullpointerException allthough reference is passed - nullpointerexception

Question

Irc client which can make multiple connections to different irc servers.
Each tab represents a server connection. I want a connection closed when its tab is closed.
When i start a connection using the menuitembutton event i construct a serverConnection object, passing it to the main controller (serverConnection con) before i launch the communication method in a new thread.
Now the problem is that when onTabClose event is fired i get a nullpointerexception when i use the reference from the main controller to change a flag so that the method running in the thread will return and eventually stop instead of using the deprecated thread.stop() method. (Keep in mind that a thread using that object is already running)
Why do i get that exception when i have already passed a reference? (garbage collector can't have touched the object since it's used in the thread and main controller reference)
serverConnection class
package jircclient;
import java.io.BufferedReader;
import java.io.BufferedWriter;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.OutputStreamWriter;
import java.net.Socket;
import java.net.UnknownHostException;
import java.util.ArrayList;
import java.util.function.Consumer;
public class serverConnection
{
//VARIABLES
public clientInfo client;
private String server_to_connect;
private String channel_to_connect;
private String serv_resp;
private int port;
private Socket socket;
private BufferedWriter writer;
private BufferedReader reader;
private ArrayList<channel> channels;
public boolean threadExitFlag = false;
//DEFAULT CONSTRUCTOR
public serverConnection() {}
//FULL CONSTRUCTOR
public serverConnection(clientInfo clientInfo, String server_to_connect, int port, String channel_to_connect) throws IOException
{
this.client = clientInfo;
this.server_to_connect = server_to_connect;
this.port = port;
this.channel_to_connect = channel_to_connect;
try
{
//Creating socket connection
this.socket = new Socket(this.server_to_connect,port);
//Socket output writer
writer = new BufferedWriter(
new OutputStreamWriter(socket.getOutputStream()));
//Socket input writer
reader = new BufferedReader(
new InputStreamReader(socket.getInputStream()));
serv_resp = null;
System.out.println("Connection established.");
}
catch(UnknownHostException exc)
{
System.out.println("ERROR: "+ exc.toString());
}
catch(IOException exc)
{
System.out.println("ERROR: "+ exc.toString());
}
finally
{
System.out.println("Closing connection.");
socket.close();
}
}
public Consumer<String> messageCallback ;
public void setMessageCallback(Consumer<String> messageCallback) {
this.messageCallback = messageCallback ;
}
//server response getter
public String getServerResponse()
{
return serv_resp;
}
public void exitThread()
{
this.threadExitFlag = true;
}
//Introduction to server and listen
public void startCommunication() throws IOException
{
//
this.socket = new Socket(this.server_to_connect,port);
writer = new BufferedWriter(new OutputStreamWriter(socket.getOutputStream()));
reader = new BufferedReader(new InputStreamReader(socket.getInputStream()));
serv_resp = null;
//
writer.write("NICK " + client.getClientNickname() + "\r\n");
writer.write("USER " + client.getClientLogin() + " 0 * : " + client.getClientRealName() + "\r\n");
writer.flush();
while ((serv_resp = reader.readLine()) != null)
{
System.out.println(serv_resp);
if (messageCallback != null)
messageCallback.accept(serv_resp);
if (serv_resp.indexOf("004") >= 0)
{
break;
}
else if (serv_resp.indexOf("433") >= 0)
{
System.out.println("Nickname is already in use.");
return;
}
}
//Get channel list
writer.write("LIST \r\n");
writer.flush();
//Join desired client
writer.write("JOIN " + channel_to_connect + "\r\n");
writer.flush();
//keep listening
while ((serv_resp = reader.readLine()) != null)
{
//check if running thread should terminate
if(threadExitFlag)
{
System.out.println("THREAD FLAG POINT");
writer.write("QUIT :Bye..");
socket.close();
return;
}
if (messageCallback != null)
messageCallback.accept(serv_resp);
if (serv_resp.startsWith("PING "))
{
this.pingPong();
} else
{
System.out.println(serv_resp);
}
}
}
//Ping respond
public void pingPong() throws IOException
{
writer.write("PONG " + serv_resp.substring(5) + "\r\n");
writer.flush();
}
mainController class
package jircclient.FXML;
import java.io.IOException;
import java.net.URL;
import java.util.ResourceBundle;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;
import java.util.logging.Level;
import java.util.logging.Logger;
import javafx.event.ActionEvent;
import javafx.event.Event;
import javafx.fxml.FXML;
import javafx.fxml.FXMLLoader;
import javafx.fxml.Initializable;
import javafx.scene.Parent;
import javafx.scene.Scene;
import javafx.scene.control.TabPane;
import javafx.scene.control.TextArea;
import javafx.stage.Stage;
import jircclient.serverConnection;
public class FXMLmainController implements Initializable
{
//VARIABLES
private connectionThreadFactory connectionThreadFactory;
private ExecutorService executor;
private int tabCounter = 0;
public serverConnection con;
//CONTROLLER VARIABLES
#FXML
TextArea txt;
#FXML
TabPane tabPane;
#FXML
private void connectServerMenuButtonAction(ActionEvent event)
{
System.out.println("You clicked connectServerButtonAction!");
FXMLLoader loader = new FXMLLoader(getClass().getResource("/jircclient/FXML/FXMLserver.fxml"));
try
{
Parent root = (Parent) loader.load();
Scene scene = new Scene(root, 320, 200);
Stage stage = new Stage();
stage.setTitle("Server Info");
stage.setResizable(false);
stage.setScene(scene);
stage.show();
FXMLserverController controller = loader.getController();
controller.initData(stage, this);
}
catch (IOException ex)
{
Logger.getLogger(FXMLserverController.class.getName()).log(Level.SEVERE, null, ex);
}
}
#FXML
private void onTabCloseEvent(Event event)
{
//Event type instead of ActionEvent because the latter didnt work
//i must be able to get a reference to the serverConnection object of the associated tab
//i have to keep a list of the tab ids and the thread objects so i can set the threadExitFlag to TRUE
System.out.println("CLOSE");
System.out.println("FLAG: "+ con.threadExitFlag);
con.exitThread();
}
#Override
public void initialize(URL url, ResourceBundle rb)
{
System.out.println("Initialize in controller!");
connectionThreadFactory = new connectionThreadFactory("Server Connection");
executor = Executors.newFixedThreadPool(5, connectionThreadFactory);
}
//setters - getters
public connectionThreadFactory getConnectionThreadFactory()
{
return connectionThreadFactory;
}
public ExecutorService getExecutorService()
{
return executor;
}
public int getTabCounter()
{
return tabCounter;
}
public void setTabCounter(int tabCounter)
{
this.tabCounter = tabCounter;
}
public void increaseTabCounter()
{
tabCounter++;
}
}
serverController class - starts when connectServerMenuButtonAction is fired and opens new window-stage
package jircclient.FXML;
import java.io.IOException;
import java.net.URL;
import java.util.ResourceBundle;
import java.util.logging.Level;
import java.util.logging.Logger;
import javafx.application.Platform;
import javafx.event.ActionEvent;
import javafx.fxml.FXML;
import javafx.fxml.FXMLLoader;
import javafx.fxml.Initializable;
import javafx.scene.control.PasswordField;
import javafx.scene.control.TextArea;
import javafx.scene.control.TextField;
import javafx.scene.layout.AnchorPane;
import javafx.stage.Stage;
import jircclient.clientInfo;
import jircclient.serverConnection;
public class FXMLserverController extends AnchorPane implements Initializable
{
//PARENT VARIABLES - REFERENCES
Stage stage;
FXMLmainController parentController;
//CONTROLLER VARIABLES
#FXML
TextField ircServerField, port, nicknameField, loginField, realNameField;
#FXML
PasswordField passwordField;
public void initData(Stage stage, FXMLmainController parentController)
{
this.stage = stage;
this.parentController = parentController;
}
#Override
public void initialize(URL url, ResourceBundle rb)
{
System.out.println("serverController reporting in!");
}
#FXML
private void connectButtonAction(ActionEvent event) throws IOException
{
//get info from text fields - initialize serverConnection
clientInfo clientInfo = new clientInfo(this.realNameField.getText(), this.nicknameField.getText(), this.loginField.getText());
serverConnection serverConnection = new serverConnection(clientInfo, ircServerField.getText(), Integer.parseInt(port.getText()), "#linux");
serverConnection.setMessageCallback(message ->
Platform.runLater(() -> ((TextArea) parentController.tabPane.lookup("#txt")).appendText(message+"\n")));
//prepare thread
Thread serverThread = parentController.getConnectionThreadFactory().newThread(() -> {
try
{
serverConnection.startCommunication();
System.out.println("Terminating Thread...");
}
catch(IOException ex)
{
Logger.getLogger(FXMLmainController.class.getName()).log(Level.SEVERE, null, ex);
}
});
//add server tab
parentController.tabPane.getTabs().add(FXMLLoader.load(getClass().getResource("/jircclient/FXML/FXMLtab.fxml")));
parentController.tabPane.getTabs().get(parentController.getTabCounter()).setText(ircServerField.getText());
parentController.increaseTabCounter();
//start thread-communication
serverThread.setDaemon(true);
parentController.getExecutorService().execute(serverThread);
parentController.con = serverConnection;
System.out.println("CON IFNO"+ parentController.con.threadExitFlag);
//close window
stage.close();
}
#FXML
private void cancelButtonAction(ActionEvent event)
{
//close window
stage.close();
}
}
fxml snippet for the #onTabCloseEvent event
<Tab xmlns:fx="http://javafx.com/fxml/1" fx:controller="jircclient.FXML.FXMLmainController" onClosed="#onTabCloseEvent">
stack trace:
Exception in thread "JavaFX Application Thread" java.lang.RuntimeException: java.lang.reflect.InvocationTargetException
at javafx.fxml.FXMLLoader$MethodHandler.invoke(FXMLLoader.java:1762)
at javafx.fxml.FXMLLoader$ControllerMethodEventHandler.handle(FXMLLoader.java:1645)
at com.sun.javafx.event.CompositeEventHandler.dispatchBubblingEvent(CompositeEventHandler.java:86)
at com.sun.javafx.event.EventHandlerManager.dispatchBubblingEvent(EventHandlerManager.java:238)
at com.sun.javafx.event.EventHandlerManager.dispatchBubblingEvent(EventHandlerManager.java:191)
at com.sun.javafx.event.BasicEventDispatcher.dispatchEvent(BasicEventDispatcher.java:58)
at com.sun.javafx.event.EventDispatchChainImpl.dispatchEvent(EventDispatchChainImpl.java:114)
at com.sun.javafx.event.EventUtil.fireEventImpl(EventUtil.java:74)
at com.sun.javafx.event.EventUtil.fireEvent(EventUtil.java:49)
at javafx.event.Event.fireEvent(Event.java:198)
at com.sun.javafx.scene.control.behavior.TabPaneBehavior.canCloseTab(TabPaneBehavior.java:152)
at com.sun.javafx.scene.control.skin.TabPaneSkin$TabHeaderSkin$5.handle(TabPaneSkin.java:1291)
at com.sun.javafx.scene.control.skin.TabPaneSkin$TabHeaderSkin$5.handle(TabPaneSkin.java:1282)
at com.sun.javafx.event.CompositeEventHandler.dispatchBubblingEvent(CompositeEventHandler.java:86)
at com.sun.javafx.event.EventHandlerManager.dispatchBubblingEvent(EventHandlerManager.java:238)
at com.sun.javafx.event.EventHandlerManager.dispatchBubblingEvent(EventHandlerManager.java:191)
at com.sun.javafx.event.CompositeEventDispatcher.dispatchBubblingEvent(CompositeEventDispatcher.java:59)
at com.sun.javafx.event.BasicEventDispatcher.dispatchEvent(BasicEventDispatcher.java:58)
at com.sun.javafx.event.EventDispatchChainImpl.dispatchEvent(EventDispatchChainImpl.java:114)
at com.sun.javafx.event.BasicEventDispatcher.dispatchEvent(BasicEventDispatcher.java:56)
at com.sun.javafx.event.EventDispatchChainImpl.dispatchEvent(EventDispatchChainImpl.java:114)
at com.sun.javafx.event.BasicEventDispatcher.dispatchEvent(BasicEventDispatcher.java:56)
at com.sun.javafx.event.EventDispatchChainImpl.dispatchEvent(EventDispatchChainImpl.java:114)
at com.sun.javafx.event.BasicEventDispatcher.dispatchEvent(BasicEventDispatcher.java:56)
at com.sun.javafx.event.EventDispatchChainImpl.dispatchEvent(EventDispatchChainImpl.java:114)
at com.sun.javafx.event.BasicEventDispatcher.dispatchEvent(BasicEventDispatcher.java:56)
at com.sun.javafx.event.EventDispatchChainImpl.dispatchEvent(EventDispatchChainImpl.java:114)
at com.sun.javafx.event.EventUtil.fireEventImpl(EventUtil.java:74)
at com.sun.javafx.event.EventUtil.fireEvent(EventUtil.java:54)
at javafx.event.Event.fireEvent(Event.java:198)
at javafx.scene.Scene$MouseHandler.process(Scene.java:3724)
at javafx.scene.Scene$MouseHandler.access$1500(Scene.java:3452)
at javafx.scene.Scene.impl_processMouseEvent(Scene.java:1728)
at javafx.scene.Scene$ScenePeerListener.mouseEvent(Scene.java:2461)
at com.sun.javafx.tk.quantum.GlassViewEventHandler$MouseEventNotification.run(GlassViewEventHandler.java:348)
at com.sun.javafx.tk.quantum.GlassViewEventHandler$MouseEventNotification.run(GlassViewEventHandler.java:273)
at java.security.AccessController.doPrivileged(Native Method)
at com.sun.javafx.tk.quantum.GlassViewEventHandler.handleMouseEvent(GlassViewEventHandler.java:382)
at com.sun.glass.ui.View.handleMouseEvent(View.java:553)
at com.sun.glass.ui.View.notifyMouse(View.java:925)
at com.sun.glass.ui.win.WinApplication._runLoop(Native Method)
at com.sun.glass.ui.win.WinApplication.lambda$null$141(WinApplication.java:102)
at com.sun.glass.ui.win.WinApplication$$Lambda$37/96639997.run(Unknown Source)
at java.lang.Thread.run(Thread.java:745)
Caused by: java.lang.reflect.InvocationTargetException
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:483)
at sun.reflect.misc.Trampoline.invoke(MethodUtil.java:71)
at sun.reflect.GeneratedMethodAccessor1.invoke(Unknown Source)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:483)
at sun.reflect.misc.MethodUtil.invoke(MethodUtil.java:275)
at javafx.fxml.FXMLLoader$MethodHandler.invoke(FXMLLoader.java:1757)
... 43 more
Caused by: java.lang.NullPointerException
at jircclient.FXML.FXMLmainController.onTabCloseEvent(FXMLmainController.java:69)
... 53 more
line 69 and 70 FXMLmainController:
System.out.println("FLAG: "+ con.threadExitFlag);
con.exitThread();