Program: 81681
Project: 81681
Buggy source:
protected Void doInBackground() throws Exception {
  task.setStatus(TaskStatus.STARTED);
  List<Picture> pics=task.pictures;
  Picture pic;
  Setting setting=((EgDownloaderWindow)mainWindow).setting;
  JTable table=((EgDownloaderWindow)mainWindow).runningTable;
  InputStream is;
  if (pics.size() != 0) {
    for (int i=0; i < pics.size(); i++) {
      pic=pics.get(i);
      if (pic.getUrl() != null && !pic.isRunning() && !pic.isCompleted()) {
        try {
          if (this.isCancelled())           return null;
          if (pic.getRealUrl() == null) {
            pic.setRealUrl(ParseEngine.getdownloadUrl(pic.getUrl(),setting));
          }
          if (this.isCancelled())           return null;
          is=WebClient.getStreamUseJava(pic.getRealUrl());
          if (this.isCancelled())           return null;
          int size=is.available();
          if (size < 1000) {
            pic.setRealUrl(null);
            System.out.println(pic.getName() + "String_Node_Str");
            continue;
          }
          FileUtil.storeStream(task.getSaveDir() + "String_Node_Str",pic.getName(),is);
          if (this.isCancelled())           return null;
          pic.setSize(size);
          pic.setTime(new SimpleDateFormat("String_Node_Str").format(new Date()));
          pic.setCompleted(true);
          task.setCurrent(task.getCurrent() + 1);
          if (this.isCancelled())           return null;
          ((EgDownloaderWindow)mainWindow).pictureDbTemplate.update(pic);
          table.updateUI();
          Tracker.println(DownloadWorker.class,task.getName() + "String_Node_Str" + pic.getName()+ "String_Node_Str");
        }
 catch (        SocketTimeoutException e) {
          System.out.println("String_Node_Str");
          continue;
        }
catch (        ConnectTimeoutException e) {
          System.out.println("String_Node_Str");
          continue;
        }
catch (        Exception e) {
          System.out.println(e.getMessage());
          continue;
        }
      }
    }
  }
  if (task.getCurrent() < pics.size()) {
    if (this.isCancelled())     return null;
    doInBackground();
  }
 else {
    task.setStatus(TaskStatus.COMPLETED);
    ((EgDownloaderWindow)mainWindow).taskDbTemplate.update(task);
  }
  return null;
}

Fixed version (ground truth):
protected Void doInBackground() throws Exception {
  task.setStatus(TaskStatus.STARTED);
  List<Picture> pics=task.pictures;
  Picture pic;
  Setting setting=((EgDownloaderWindow)mainWindow).setting;
  JTable table=((EgDownloaderWindow)mainWindow).runningTable;
  InputStream is;
  if (pics.size() != 0) {
    for (int i=0; i < pics.size(); i++) {
      pic=pics.get(i);
      if (pic.getUrl() != null && !pic.isRunning() && !pic.isCompleted()) {
        try {
          if (this.isCancelled())           return null;
          if (pic.getRealUrl() == null) {
            pic.setRealUrl(ParseEngine.getdownloadUrl(pic.getUrl(),setting));
          }
          if (this.isCancelled())           return null;
          is=WebClient.getStreamUseJava(pic.getRealUrl());
          if (this.isCancelled())           return null;
          int size=is.available();
          if (size < 1000) {
            pic.setRealUrl(null);
            System.out.println(pic.getName() + "String_Node_Str");
            continue;
          }
          FileUtil.storeStream(task.getSaveDir(),pic.getName(),is);
          if (this.isCancelled())           return null;
          pic.setSize(size);
          pic.setTime(new SimpleDateFormat("String_Node_Str").format(new Date()));
          pic.setCompleted(true);
          task.setCurrent(task.getCurrent() + 1);
          if (this.isCancelled())           return null;
          ((EgDownloaderWindow)mainWindow).pictureDbTemplate.update(pic);
          table.updateUI();
          Tracker.println(DownloadWorker.class,task.getName() + "String_Node_Str" + pic.getName()+ "String_Node_Str");
        }
 catch (        SocketTimeoutException e) {
          System.out.println("String_Node_Str");
          continue;
        }
catch (        ConnectTimeoutException e) {
          System.out.println("String_Node_Str");
          continue;
        }
catch (        Exception e) {
          System.out.println(e.getMessage());
          continue;
        }
      }
    }
  }
  if (task.getCurrent() < pics.size()) {
    if (this.isCancelled())     return null;
    doInBackground();
  }
 else {
    task.setStatus(TaskStatus.COMPLETED);
    ((EgDownloaderWindow)mainWindow).taskDbTemplate.update(task);
  }
  return null;
}