Program: 78362
Project: 78362
Buggy source:
/** 
 * Perform an action when the user's click on a today's assignment.
 * @param todayAssignmentAe the today's assignments ActionEvent.
 * @param proxy the client proxy.
 * @param guiHome the GUIHome in use.
 */
protected void clickOnTodayAssignment(ActionEvent todayAssignmentAe,Proxy proxy,GUIHome guiHome){
  if (!(todayAssignmentAe.getActionCommand().equals("String_Node_Str"))) {
    JButton pressedButton=(JButton)todayAssignmentAe.getSource();
    StringTokenizer cmdToken=new StringTokenizer(buttonTodayAssignment[0].getText(),"String_Node_Str");
    String cmd=cmdToken.nextToken();
    if (cmd.equals("String_Node_Str")) {
      calendarState=CalendarState.NORMAL;
      SimpleDateFormat dateMonth=new SimpleDateFormat("String_Node_Str");
      Date date=new Date();
      String strMonthNumber=dateMonth.format(date);
      int monthNumber=Integer.parseInt(strMonthNumber);
      try {
        updateCalendar(monthNumber,proxy);
      }
 catch (      ParseException e) {
        e.printStackTrace();
      }
      HashMap<Integer,Assignment> listAssignment=proxy.getAssignmentList();
      Assignment a=listAssignment.get(pressedButton.getDisplayedMnemonicIndex());
      if (guiHome instanceof GUICustomer) {
        GUIAssignmentInformationCustomer guiAssignment=new GUIAssignmentInformationCustomer(a,email,(GUICustomer)guiHome);
        guiAssignment.setVisible(true);
      }
 else {
        GUIAssignmentInformationDogsitter guiAssignment=new GUIAssignmentInformationDogsitter(a,email,(GUIDogSitter)guiHome);
        guiAssignment.setVisible(true);
      }
    }
  }
}

Fixed version (ground truth):
/** 
 * Perform an action when the user's click on a today's assignment.
 * @param todayAssignmentAe the today's assignments ActionEvent.
 * @param proxy the client proxy.
 * @param guiHome the GUIHome in use.
 */
protected void clickOnTodayAssignment(ActionEvent todayAssignmentAe,Proxy proxy,GUIHome guiHome){
  if (!(todayAssignmentAe.getActionCommand().equals("String_Node_Str"))) {
    JButton pressedButton=(JButton)todayAssignmentAe.getSource();
    StringTokenizer cmdToken=new StringTokenizer(buttonTodayAssignment[0].getText(),"String_Node_Str");
    String cmd=cmdToken.nextToken();
    if (cmd.equals("String_Node_Str")) {
      calendarState=CalendarState.NORMAL;
      SimpleDateFormat dateMonth=new SimpleDateFormat("String_Node_Str");
      Date date=new Date();
      String strMonthNumber=dateMonth.format(date);
      int monthNumber=Integer.parseInt(strMonthNumber);
      try {
        updateCalendar(proxy);
      }
 catch (      ParseException e) {
        e.printStackTrace();
      }
      HashMap<Integer,Assignment> listAssignment=proxy.getAssignmentList();
      Assignment a=listAssignment.get(pressedButton.getDisplayedMnemonicIndex());
      if (guiHome instanceof GUICustomer) {
        GUIAssignmentInformationCustomer guiAssignment=new GUIAssignmentInformationCustomer(a,email,(GUICustomer)guiHome);
        guiAssignment.setVisible(true);
      }
 else {
        GUIAssignmentInformationDogsitter guiAssignment=new GUIAssignmentInformationDogsitter(a,email,(GUIDogSitter)guiHome);
        guiAssignment.setVisible(true);
      }
    }
  }
}