Program: 81659
Project: 81659
Buggy source:
public void doWork(Window addFormDialog,MouseEvent event){
  AddFormDialog this_=(AddFormDialog)addFormDialog;
  String url=this_.urlField.getText().trim();
  String saveDir=this_.saveDirField.getText().trim();
  String tag=this_.tagField.getText().trim();
  if ("String_Node_Str".equals(url)) {
    JOptionPane.showMessageDialog(this_,"String_Node_Str");
  }
 else   if ("String_Node_Str".equals(saveDir)) {
    JOptionPane.showMessageDialog(this_,"String_Node_Str");
  }
 else {
    if ("String_Node_Str".equals(tag)) {
      tag="String_Node_Str";
    }
    EgDownloaderWindow mainWindow=(EgDownloaderWindow)this_.mainWindow;
    if (isValidUrl(mainWindow.setting,url)) {
      if ("String_Node_Str".equals(url.substring(url.length() - 1,url.length()))) {
        url=url.substring(0,url.length() - 1);
      }
      if (!mainWindow.taskDbTemplate.exsits("String_Node_Str",url)) {
        if (((EgDownloaderWindow)this_.mainWindow).creatingWindow == null) {
          ((EgDownloaderWindow)this_.mainWindow).creatingWindow=new CreatingWindow(mainWindow);
        }
        String tags=setting.getTags();
        if (!"String_Node_Str".equals(tag)) {
          if (tags == null) {
            setting.setTags(tag);
            mainWindow.settingDbTemplate.update(setting);
          }
 else {
            String[] tagsArr=tags.split("String_Node_Str" + Setting.TAGSPLIT);
            if (!ArrayUtil.exists(tagsArr,tag)) {
              setting.setTags(tag + Setting.TAGSPLIT + setting.getTags());
            }
 else {
              tags=change(tags.split("String_Node_Str" + Setting.TAGSPLIT),tag,Setting.TAGSPLIT);
              setting.setTags(tags);
            }
            mainWindow.settingDbTemplate.update(setting);
          }
          initOrUpdateTagComboBox(setting);
        }
        Task task=new Task(url,saveDir);
        task.setTag(tag);
        CreateWorker worker=new CreateWorker(task,mainWindow);
        worker.execute();
      }
 else {
        JOptionPane.showMessageDialog(this_,"String_Node_Str");
      }
    }
 else {
      JOptionPane.showMessageDialog(this_,"String_Node_Str");
    }
  }
}

Fixed version (ground truth):
public void doWork(Window addFormDialog,MouseEvent event){
  AddFormDialog this_=(AddFormDialog)addFormDialog;
  String url=this_.urlField.getText().trim();
  String saveDir=this_.saveDirField.getText().trim();
  String tag=this_.tagField.getText().trim();
  if ("String_Node_Str".equals(url)) {
    JOptionPane.showMessageDialog(this_,"String_Node_Str");
  }
 else   if ("String_Node_Str".equals(saveDir)) {
    JOptionPane.showMessageDialog(this_,"String_Node_Str");
  }
 else {
    if ("String_Node_Str".equals(tag)) {
      tag="String_Node_Str";
    }
    EgDownloaderWindow mainWindow=(EgDownloaderWindow)this_.mainWindow;
    if (isValidUrl(mainWindow.setting,url)) {
      if ("String_Node_Str".equals(url.substring(url.length() - 1,url.length()))) {
        url=url.substring(0,url.length() - 1);
      }
      if (!mainWindow.taskDbTemplate.exsits("String_Node_Str",url)) {
        if (addTaskBtn.isEnabled()) {
          addTaskBtn.setEnabled(false);
        }
 else {
          return;
        }
        if (((EgDownloaderWindow)this_.mainWindow).creatingWindow == null) {
          ((EgDownloaderWindow)this_.mainWindow).creatingWindow=new CreatingWindow(mainWindow);
        }
        String tags=setting.getTags();
        if (!"String_Node_Str".equals(tag)) {
          if (tags == null) {
            setting.setTags(tag);
            mainWindow.settingDbTemplate.update(setting);
          }
 else {
            String[] tagsArr=tags.split("String_Node_Str" + Setting.TAGSPLIT);
            if (!ArrayUtil.exists(tagsArr,tag)) {
              setting.setTags(tag + Setting.TAGSPLIT + setting.getTags());
            }
 else {
              tags=change(tags.split("String_Node_Str" + Setting.TAGSPLIT),tag,Setting.TAGSPLIT);
              setting.setTags(tags);
            }
            mainWindow.settingDbTemplate.update(setting);
          }
          initOrUpdateTagComboBox(setting);
        }
        Task task=new Task(url,saveDir);
        task.setTag(tag);
        CreateWorker worker=new CreateWorker(task,mainWindow);
        worker.execute();
        addTaskBtn.setEnabled(true);
      }
 else {
        JOptionPane.showMessageDialog(this_,"String_Node_Str");
      }
    }
 else {
      JOptionPane.showMessageDialog(this_,"String_Node_Str");
    }
  }
}