Having problem in Displaying Text in textarea through a Thread.

Question

Hi freinds,
I am not able to get the Text displayed in Textarea at the same time when it is appended to textarea from a thread.... all the text is displayed at a single go after the program finishes the execution.
import javax.swing.*;
import java.util.*;
import java.io.*;
import java.awt.event.*;
public class BaseFrame extends JFrame implements ActionListener
     JComboBox Jbx = new JComboBox();
     JButton Bn1 = new JButton("Start");
     JButton Bn2 = new JButton("Restart");
     JButton Bn3 = new JButton("Stop");
     JTextArea Tx = new JTextArea();
     public BaseFrame()
          initProp();
          contents();
     protected void initProp()
          setSize(550,350);
          setVisible(true);
          setLocationRelativeTo(null);
          setResizable(false);
          setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
          getContentPane().setLayout(new SpringLayout());
     protected void contents()
          JLabel lbl= new JLabel("Select the Server : ");
          JScrollPane Js = new JScrollPane();
          JScrollPane Js1 = new JScrollPane();
          JPanel pn= new JPanel();
          Jbx.addItem(" ausserver");
          Jbx.addItem(" Inc2Server");
          Jbx.addItem(" Inc2NZL");
          pn.setLayout(new SpringLayout());
          pn.add(lbl,new SpringLayout.Constraints(
               Spring.constant(20),
               Spring.constant(20),
               Spring.constant(130),
               Spring.constant(25)));
          pn.add(Jbx,new SpringLayout.Constraints(
               Spring.constant(130),
               Spring.constant(20),
               Spring.constant(200),
               Spring.constant(22)));
          pn.add(Bn1,new SpringLayout.Constraints(
               Spring.constant(20),
               Spring.constant(50),
               Spring.constant(100),
               Spring.constant(22)));
          pn.add(Bn2,new SpringLayout.Constraints(
               Spring.constant(140),
               Spring.constant(50),
               Spring.constant(100),
               Spring.constant(22)));
          pn.add(Bn3,new SpringLayout.Constraints(
               Spring.constant(260),
               Spring.constant(50),
               Spring.constant(100),
               Spring.constant(22)));
          Js1.getViewport().add(Tx);
          pn.add(Js1,new SpringLayout.Constraints(
               Spring.constant(3),
               Spring.constant(80),
               Spring.constant(535),
               Spring.constant(238)));
          Js.getViewport().add(pn);
          getContentPane().add(Js,new SpringLayout.Constraints(
               Spring.constant(0),
               Spring.constant(0),
               Spring.constant(544),
               Spring.constant(324)));
          Bn1.addActionListener(this);
          Bn2.addActionListener(this);
          Bn3.addActionListener(this);
     public void actionPerformed(ActionEvent ae)
          if(ae.getActionCommand() == "Start")
               try{
                         Start();
               catch(IOException ie)
                    Tx.append("Cannot find File\n");
          if(ae.getActionCommand() == "Stop")
               try{
                         Stop();
               catch(IOException ie)
                    Tx.append("Cannot find File\n");
          if(ae.getActionCommand() == "Restart")
               try{
                         Stop();
                         Start();
               catch(IOException ie)
                    Tx.append("Cannot find File\n");
     void Start() throws IOException
          FileWriter wr = new FileWriter("dk.bat");
          wr.write("@echo off\n");
          wr.write("\"C:/Program Files/WebSphere/AppServer/bin/startserver\"" + Jbx.getSelectedItem());
          wr.close();
          Tx.append("\nStarting Server" + Jbx.getSelectedItem() +"\n");
          RunCmd rn = new RunCmd();
          rn.runComm("dk.bat");
          Tx.append("\nServer Restarted");
     void Stop() throws IOException
          char[] buf={1,2,3,4};
          String str=(String)Jbx.getSelectedItem();
          FileReader fr= new FileReader("C:/Progra~1/WebSphere/AppServer/logs/"
                                        + str.trim() +"/"+str.trim()+".pid");
          fr.read(buf,0,4);
          fr.close();
          System.out.println(buf);
          String str1=new String(buf);
          FileWriter wr = new FileWriter("dk.bat");
          wr.write("@echo off\n");
          wr.write("taskkill /pid " + str1 + " /f");
          wr.close();
          Tx.append("\nStopping Server" + str +" with Process Id " str1 "\n");
          RunCmd rn = new RunCmd();
          rn.runComm("dk.bat");
          Tx.append("\nStopped the Server");
     class StreamGobbler extends Thread
          InputStream is;
          String type;
          OutputStream os;
          StreamGobbler(InputStream is, String type)
               this.is = is;
               this.type = type;
          public void run()
               try
                    InputStreamReader isr = new InputStreamReader(is);
                    BufferedReader br = new BufferedReader(isr);
                    String line=null;
                    while ( (line = br.readLine()) != null)
                         Tx.append(line + "\n");
               } catch (IOException ioe)
                         ioe.printStackTrace();
     public class RunCmd
          public int runComm(String str)
               int exitVal = 0;
               try
                    Runtime rt = Runtime.getRuntime();
                    Process proc = rt.exec(str);
                    StreamGobbler errorGobbler = new
                         StreamGobbler(proc.getErrorStream(), "ERROR");
                    StreamGobbler outputGobbler = new
                         StreamGobbler(proc.getInputStream(), "OUTPUT");
                    errorGobbler.start();
                    outputGobbler.start();
                    exitVal = proc.waitFor();
                    System.out.println("ExitValue: " + exitVal );
               } catch (Throwable t)
                    t.printStackTrace();
               return exitVal;
Kindly look into this ..if someone has a clue what is going wrong where....plz inform me...thanks in advance.

Answer 1

Use the "code" formatting tags when posting code so the code retains its original formatting.
I didn't really look at your code but this type of problem is usually caused by executing a long running task in the Event Thread. Therefore the GUI can't repaint itself until the long running task is finished. Solution is to create a separate thread for the long running task.
Something like this:
http://forum.java.sun.com/thread.jspa?forumID=257&threadID=437592