Program: 20955
Project: 20955
Buggy source:
@Override public void handlePremium(DownloadLink downloadLink,Account account) throws Exception {
  requestFileInformation(downloadLink);
  login(account);
  br.getPage(downloadLink.getDownloadURL());
  String url=null;
  if (downloadLink.getStringProperty("String_Node_Str","String_Node_Str").equalsIgnoreCase("String_Node_Str")) {
    url=br.getRedirectLocation();
  }
 else {
    if (!br.containsHTML("String_Node_Str")) {
      String passCode;
      DownloadLink link=downloadLink;
      Form form=br.getFormbyProperty("String_Node_Str","String_Node_Str");
      if (link.getStringProperty("String_Node_Str",null) == null) {
        passCode=Plugin.getUserInput(null,link);
      }
 else {
        passCode=link.getStringProperty("String_Node_Str",null);
      }
      form.put("String_Node_Str",passCode);
      br.submitForm(form);
      form=br.getFormbyProperty("String_Node_Str","String_Node_Str");
      if (form != null && !br.containsHTML("String_Node_Str")) {
        link.setProperty("String_Node_Str",null);
        throw new PluginException(LinkStatus.ERROR_FATAL,JDL.L("String_Node_Str","String_Node_Str"));
      }
 else {
        link.setProperty("String_Node_Str",passCode);
      }
    }
    url=getDownloadUrl();
  }
  if (url == null)   throw new PluginException(LinkStatus.ERROR_PLUGIN_DEFECT);
  dl=jd.plugins.BrowserAdapter.openDownload(br,downloadLink,url,true,0);
  if (!dl.getConnection().isContentDisposition()) {
    logger.info("String_Node_Str");
    br.followConnection();
    throw new PluginException(LinkStatus.ERROR_PLUGIN_DEFECT);
  }
  dl.startDownload();
}

Fixed version (ground truth):
@Override public void handlePremium(DownloadLink downloadLink,Account account) throws Exception {
  requestFileInformation(downloadLink);
  login(account);
  br.getPage(downloadLink.getDownloadURL());
  String url=null;
  if (downloadLink.getStringProperty("String_Node_Str","String_Node_Str").equalsIgnoreCase("String_Node_Str")) {
    logger.info("String_Node_Str");
    url=br.getRedirectLocation();
  }
 else {
    if (br.getRedirectLocation() != null)     br.getPage(br.getRedirectLocation());
    if (!br.containsHTML("String_Node_Str")) {
      String passCode;
      DownloadLink link=downloadLink;
      Form form=br.getFormbyProperty("String_Node_Str","String_Node_Str");
      if (link.getStringProperty("String_Node_Str",null) == null) {
        passCode=Plugin.getUserInput(null,link);
      }
 else {
        passCode=link.getStringProperty("String_Node_Str",null);
      }
      form.put("String_Node_Str",passCode);
      br.submitForm(form);
      form=br.getFormbyProperty("String_Node_Str","String_Node_Str");
      if (form != null && !br.containsHTML("String_Node_Str")) {
        link.setProperty("String_Node_Str",null);
        throw new PluginException(LinkStatus.ERROR_FATAL,JDL.L("String_Node_Str","String_Node_Str"));
      }
 else {
        link.setProperty("String_Node_Str",passCode);
      }
    }
    url=getDownloadUrl();
  }
  if (url == null)   throw new PluginException(LinkStatus.ERROR_PLUGIN_DEFECT);
  br.setFollowRedirects(true);
  dl=jd.plugins.BrowserAdapter.openDownload(br,downloadLink,url,true,0);
  if (!dl.getConnection().isContentDisposition()) {
    logger.info("String_Node_Str");
    br.followConnection();
    throw new PluginException(LinkStatus.ERROR_PLUGIN_DEFECT);
  }
  dl.startDownload();
}