Hi Patricia,

Here is an SSCCE:

import java.awt.*;
import java.awt.event.*;
import java.util.Vector;

public class DynamicPathGenerator extends Frame implements Runnable {

    /**
    * Member variables
    *
    * @param clock Thread that provides the ticks for the main program
    * @param clock_period Shows how often the clock ticks
    * @param serialVersionUID Id needed for serialization
    * @param ta TextArea for system outputs
    */
    Thread clock;
    boolean threadsSuspended = false;
    static final int clock_period = 1000;
    private static final long serialVersionUID = 1L;
    TextArea  ta = new TextArea("DynamicPathGenerator ver 1.0\n\n", 10,
35);
    int counter;

    /**
    * AWT classes
    */

    /**
    * Window closing class
    */
    class MyWindowCloser extends WindowAdapter {

         public void windowClosing(WindowEvent e) {

              System.exit(0);

         } // method windowClosing

    } // class MyWindowCloser

    /**
    * Start button listener
    */
    class startListener implements ActionListener {

        public void actionPerformed (ActionEvent e) {

            ta.append("DynamicPathGenerator> simulation started\n");
            threadsSuspended = false;

            if(!clock.isAlive()) {

                clock.start();

            }
            else {

                synchronized(this) {
                    notifyAll();

                }
            }

        } // method actionPerformed

    } // class startListener

    /**
    * Stop button listener
    */
    class stopListener implements ActionListener {

        public void actionPerformed (ActionEvent e) {

            ta.append("DynamicPathGenerator> simulation stopped\n");

            threadsSuspended = true;

        } // method actionPerformed

    } // class stopListener

    /**
    * Constructor of the class.
    */
    public DynamicPathGenerator() { // CONSTRUCTOR

        clock = new Thread(this);

       Button start = new Button("Simulation starten");   //Gombok
hozz?ad?sa
       Button stop = new Button("Simulation beenden");

       Panel p1 = new Panel(new GridLayout(2,3));
       Panel p3 = new Panel();

       // add panel elements

       p1.add(start);
       p1.add(stop);
       p3.add(ta);

       // arrange panel elements

       add(p1, BorderLayout.NORTH);  add(p3, BorderLayout.SOUTH);

       // adding listeners

       start.addActionListener(new startListener () );
       stop.addActionListener(new stopListener () );

       addWindowListener( new MyWindowCloser () );

    } // CONSTRUCTOR

    public void putText(String text) {
      ta.append(text);
    }

    public void run()
    {
        try {

        while(true)
        {
            this.putText("F\n");

                this.counter++;
                this.putText(new Integer(counter).toString());
                Thread.sleep(clock_period);
               synchronized(this) {
                   while (threadsSuspended)
                       wait();
               }

        } // while

        } catch (InterruptedException e) {

        }

        return;

    } // method run

    /**
    * The main method
    */
    public static void main(String argv[]) throws Exception {

        DynamicPathGenerator dpg = new DynamicPathGenerator();
        dpg.pack();
        dpg.setVisible(true);

     } // method main

} // class DynamicPathGenerator

I am really quite newby with programming threads, so I think I still
have some basic problems of understanding the concepts of thread
programming.

I read the official sun docs on the issue and I used the codes
there... So thanks if someone can point out the bug in the code above.

Best,

korcs