Help Please! Exception Error with Threads

Question

In my program i get this:
java.lang.NullPointerException
     at kmess$SocketClient.run(kmess.java:336)
     at java.lang.Thread.run(Thread.java:536)line 336 refers to this part of my code:
public void run()
          if(getdata.equals(Thread.currentThread()) )
               System.out.println("running getdata thread");
               getdatamethod();
          if(senddataThread.equals(Thread.currentThread()) )
               System.out.println("running senddataThread thread");
               senddatamethod();
}Now, here is the rest of this class that this method is in:
class SocketClient extends JFrame implements Runnable {
     Socket socket = null;
   PrintWriter out = null;
   BufferedReader in = null;
          String text = null;
     Thread getdata;
   SocketClient(){
     public void listenSocket() {
     if ( connected==("2") ) {
//Create socket connection
     try{
       socket = new Socket("0.0.0.0", 4444);
       out = new PrintWriter(socket.getOutputStream(), true);
       in = new BufferedReader(new InputStreamReader(socket.getInputStream()));
     } catch (UnknownHostException e) {
       System.out.println("Unknown host: host your connecting to");
       System.exit(1);
     } catch  (IOException e) {
       System.out.println("No I/O");
       System.exit(1);
               connected = "1";
               out2 = out;
               in2 = in;
     if (thisclient==("1"))
          creategetdatathread();
     if (thisclient==("2"))
     { Thread senddataThread = new Thread(this);
          senddataThread.equals(Thread.currentThread());
          System.out.println("current thread is after thisclient = 2 " + Thread.currentThread() + senddataThread);
          senddataThread.start();
          thisclient = "3";
     senddata();
public void creategetdatathread()
System.out.println("In creategetdatathread");
     Thread getdata = new Thread(this);
          getdata.equals(Thread.currentThread());
          System.out.println("current thread is after thisclient = 1 " + Thread.currentThread() + senddataThread);
          thisclient = "4";
          getdata.start();
public void run()
          if(getdata.equals(Thread.currentThread()) )
               System.out.println("running getdata thread");
               getdatamethod();
          if(senddataThread.equals(Thread.currentThread()) )
               System.out.println("running senddataThread thread");
               senddatamethod();
public void senddatamethod() {
while(true) {
       try{
       String line = in2.readLine();
          if (line != null) {
          out2.println(line);
       } catch (IOException e){
      System.out.println("Read failed");
             System.exit(1);
          try { Thread.sleep(2000); }
               catch(InterruptedException e) {}
public void getdatamethod() {
while(true) {
       try{
       String line = in2.readLine();
          if (line != null)
          messlistArea.append("Message:" + line + "\n");
       } catch (IOException e){
      System.out.println("Read failed");
             System.exit(1);
          try { Thread.sleep(2000); }
               catch(InterruptedException e) {}
public void senddata() {
     //Send data over socket
     System.out.println("in send data method");
          String text = messageArea.getText();
          out2.println(text);
       messageArea.setText(new String(""));
//Receive text from server
       try{
       String line = in2.readLine();
          if (thisclient==("4"))
          messlistArea.append("Message:" + line + "\n");
       } catch (IOException e){
      System.out.println("Read failed");
             System.exit(1);
}QUESTION: how do i prevent this error, and therefore enable those threads in that run method to run? thanks.

Answer 1

Well I don't really want to get into the design of your solution but there are a lot of errors in the code you've posted. I presume the code you posted isn't the code you're running as there are declarations missing and it won't compile. But the fundamental answer to your question is that to avoid the error you initially described you need to make sure your reading and writing threads are fully initialised before your frame thread starts running.