Program: 20874
Project: 20874
Buggy source:
@Override public void handleFree(DownloadLink link) throws Exception {
  requestFileInformation(link);
  br.setFollowRedirects(true);
  if (link.getDownloadURL().contains("String_Node_Str")) {
    String dllink;
    dllink=br.getURL();
    if (dllink == null)     throw new PluginException(LinkStatus.ERROR_PLUGIN_DEFECT);
    link.setFinalFileName(null);
    dl=jd.plugins.BrowserAdapter.openDownload(br,link,dllink,false,1);
    dl.startDownload();
  }
 else {
    String infolink=link.getDownloadURL();
    if (br.containsHTML("String_Node_Str")) {
      Form form=br.getForm(0);
      if (form == null)       throw new PluginException(LinkStatus.ERROR_PLUGIN_DEFECT);
      String passCode=null;
      if (link.getStringProperty("String_Node_Str",null) == null) {
        passCode=Plugin.getUserInput("String_Node_Str",link);
      }
 else {
        passCode=link.getStringProperty("String_Node_Str",null);
      }
      form.put("String_Node_Str",passCode);
      br.submitForm(form);
      if (br.containsHTML("String_Node_Str")) {
        logger.warning("String_Node_Str");
        link.setProperty("String_Node_Str",null);
        throw new PluginException(LinkStatus.ERROR_RETRY);
      }
      if (passCode != null) {
        link.setProperty("String_Node_Str",passCode);
      }
    }
    String infolink2=infolink.replaceAll("String_Node_Str","String_Node_Str");
    br.getPage(infolink2);
    String dllink=br.getRegex("String_Node_Str").getMatch(0);
    if (dllink == null)     dllink=br.getRegex("String_Node_Str").getMatch(0);
    if (dllink == null)     throw new PluginException(LinkStatus.ERROR_PLUGIN_DEFECT);
    dl=jd.plugins.BrowserAdapter.openDownload(br,link,dllink,false,1);
    dl.startDownload();
  }
}

Fixed version (ground truth):
@Override public void handleFree(DownloadLink link) throws Exception {
  requestFileInformation(link);
  br.setFollowRedirects(true);
  if (link.getDownloadURL().contains("String_Node_Str")) {
    String dllink;
    dllink=br.getURL();
    if (dllink == null)     throw new PluginException(LinkStatus.ERROR_PLUGIN_DEFECT);
    link.setFinalFileName(null);
    dl=jd.plugins.BrowserAdapter.openDownload(br,link,dllink,false,1);
    dl.startDownload();
  }
 else {
    String infolink=link.getDownloadURL();
    if (br.containsHTML("String_Node_Str")) {
      Form form=br.getForm(0);
      if (form == null)       throw new PluginException(LinkStatus.ERROR_PLUGIN_DEFECT);
      String passCode=null;
      if (link.getStringProperty("String_Node_Str",null) == null) {
        passCode=Plugin.getUserInput("String_Node_Str",link);
      }
 else {
        passCode=link.getStringProperty("String_Node_Str",null);
      }
      form.put("String_Node_Str",passCode);
      br.submitForm(form);
      if (br.containsHTML("String_Node_Str")) {
        logger.warning("String_Node_Str");
        link.setProperty("String_Node_Str",null);
        throw new PluginException(LinkStatus.ERROR_RETRY);
      }
      if (passCode != null) {
        link.setProperty("String_Node_Str",passCode);
      }
    }
    String infolink2=infolink.replaceAll("String_Node_Str","String_Node_Str");
    br.getPage(infolink2);
    String dllink=br.getRegex("String_Node_Str").getMatch(0);
    if (dllink == null)     dllink=br.getRegex("String_Node_Str").getMatch(0);
    if (dllink == null)     throw new PluginException(LinkStatus.ERROR_PLUGIN_DEFECT);
    dl=jd.plugins.BrowserAdapter.openDownload(br,link,dllink,false,1);
    if (dl.getConnection().getContentType().contains("String_Node_Str")) {
      br.followConnection();
      throw new PluginException(LinkStatus.ERROR_PLUGIN_DEFECT);
    }
    dl.startDownload();
  }
}