Program: 44364
Project: 44364
Buggy source:
public ControlPanel(final DebugPanel parent){
  super(new FlowLayout(FlowLayout.LEFT));
  if (parent == null)   throw new NullPointerException();
  final Controller controller=parent.controller;
  JButton back=new JButton("String_Node_Str");
  back.addActionListener(new ActionListener(){
    public void actionPerformed(    ActionEvent e){
synchronized (controller) {
        if (controller.isRunning())         return;
        parent.beginStep();
        try {
          controller.stepBack();
        }
 catch (        IllegalOpcodeException ex) {
        }
        parent.endStep();
      }
    }
  }
);
  add(back);
  JButton step=new JButton("String_Node_Str");
  step.addActionListener(new ActionListener(){
    public void actionPerformed(    ActionEvent e){
synchronized (controller) {
        if (controller.isRunning() || parent.machine.isHalted())         return;
        parent.beginStep();
        try {
          controller.step();
        }
 catch (        IllegalOpcodeException ex) {
        }
        parent.endStep();
      }
    }
  }
);
  add(step);
  JButton resume=new JButton("String_Node_Str");
  resume.addActionListener(new ActionListener(){
    public void actionPerformed(    ActionEvent e){
      if (controller.isRunning())       return;
      parent.beginRun();
      new Thread("String_Node_Str"){
        public void run(){
          controller.run();
          try {
            SwingUtilities.invokeAndWait(new Runnable(){
              public void run(){
                parent.endRun();
              }
            }
);
          }
 catch (          InvocationTargetException e) {
          }
catch (          InterruptedException e) {
          }
        }
      }
.start();
    }
  }
);
  add(resume);
  JButton suspend=new JButton("String_Node_Str");
  suspend.addActionListener(new ActionListener(){
    public void actionPerformed(    ActionEvent e){
      controller.suspend();
    }
  }
);
  add(suspend);
}

Fixed version (ground truth):
public ControlPanel(final DebugPanel parent){
  super(new FlowLayout(FlowLayout.LEFT));
  if (parent == null)   throw new NullPointerException();
  final Controller controller=parent.controller;
  JButton back=new JButton("String_Node_Str");
  back.addActionListener(new ActionListener(){
    public void actionPerformed(    ActionEvent e){
synchronized (controller) {
        if (controller.isRunning())         return;
        parent.beginStep();
        try {
          controller.stepBack();
        }
 catch (        IllegalOpcodeException ex) {
        }
        parent.endStep();
      }
    }
  }
);
  add(back);
  JButton step=new JButton("String_Node_Str");
  step.addActionListener(new ActionListener(){
    public void actionPerformed(    ActionEvent e){
synchronized (controller) {
        if (controller.isRunning() || controller.getMachine().isHalted())         return;
        parent.beginStep();
        try {
          controller.step();
        }
 catch (        IllegalOpcodeException ex) {
        }
        parent.endStep();
      }
    }
  }
);
  add(step);
  JButton resume=new JButton("String_Node_Str");
  resume.addActionListener(new ActionListener(){
    public void actionPerformed(    ActionEvent e){
      if (controller.isRunning())       return;
      parent.beginRun();
      new Thread("String_Node_Str"){
        public void run(){
          controller.run();
          try {
            SwingUtilities.invokeAndWait(new Runnable(){
              public void run(){
                parent.endRun();
              }
            }
);
          }
 catch (          InvocationTargetException e) {
          }
catch (          InterruptedException e) {
          }
        }
      }
.start();
    }
  }
);
  add(resume);
  JButton suspend=new JButton("String_Node_Str");
  suspend.addActionListener(new ActionListener(){
    public void actionPerformed(    ActionEvent e){
      controller.suspend();
    }
  }
);
  add(suspend);
}