Program: 20996
Project: 20996
Buggy source:
public void handleFree(DownloadLink downloadLink) throws Exception {
  setBrowserExclusive();
  requestFileInformation(downloadLink);
  String link=downloadLink.getDownloadURL();
  br.getPage(link);
  if (br.getRedirectLocation() != null) {
    link=br.getRedirectLocation().replaceAll("String_Node_Str","String_Node_Str");
    br.getPage(link);
  }
  if (br.containsHTML(DOWNLOAD_NOTALLOWED)) {
    throw new PluginException(LinkStatus.ERROR_TEMPORARILY_UNAVAILABLE,20 * 60 * 1000l);
  }
  Form form=br.getFormBySubmitvalue("String_Node_Str");
  if (form != null) {
    br.submitForm(form);
  }
  if (br.containsHTML("String_Node_Str"))   throw new PluginException(LinkStatus.ERROR_TEMPORARILY_UNAVAILABLE,JDL.L("String_Node_Str","String_Node_Str"),10 * 60 * 1000l);
  String wait=br.getRegex("String_Node_Str").getMatch(0);
  if (wait != null)   throw new PluginException(LinkStatus.ERROR_IP_BLOCKED,Regex.getMilliSeconds(wait));
  if (br.containsHTML("String_Node_Str"))   throw new PluginException(LinkStatus.ERROR_IP_BLOCKED,null,2 * 60 * 1001l);
  if (br.getRedirectLocation() != null && br.getRedirectLocation().indexOf("String_Node_Str") > 0) {
    throw new PluginException(LinkStatus.ERROR_RETRY);
  }
  String dllink=br.getRegex("String_Node_Str").getMatch(0);
  dl=jd.plugins.BrowserAdapter.openDownload(br,downloadLink,dllink,true,1);
  URLConnectionAdapter con=dl.getConnection();
  if (Plugin.getFileNameFromHeader(con) == null || Plugin.getFileNameFromHeader(con).indexOf("String_Node_Str") >= 0) {
    con.disconnect();
    throw new PluginException(LinkStatus.ERROR_RETRY);
  }
  if (!con.isContentDisposition()) {
    con.disconnect();
    throw new PluginException(LinkStatus.ERROR_TEMPORARILY_UNAVAILABLE,10 * 60 * 1000l);
  }
  dl.startDownload();
}

Fixed version (ground truth):
public void handleFree(DownloadLink downloadLink) throws Exception {
  setBrowserExclusive();
  requestFileInformation(downloadLink);
  String link=downloadLink.getDownloadURL();
  br.getPage(link);
  if (br.getRedirectLocation() != null) {
    link=br.getRedirectLocation().replaceAll("String_Node_Str","String_Node_Str");
    br.getPage(link);
  }
  if (br.containsHTML(DOWNLOAD_NOTALLOWED)) {
    throw new PluginException(LinkStatus.ERROR_TEMPORARILY_UNAVAILABLE,20 * 60 * 1000l);
  }
  String dllink=br.getRegex("String_Node_Str").getMatch(0);
  if (dllink != null) {
    dl=jd.plugins.BrowserAdapter.openDownload(br,downloadLink,dllink,true,1);
    URLConnectionAdapter con=dl.getConnection();
    if (Plugin.getFileNameFromHeader(con) == null || Plugin.getFileNameFromHeader(con).indexOf("String_Node_Str") >= 0) {
      con.disconnect();
      throw new PluginException(LinkStatus.ERROR_RETRY);
    }
    if (!con.isContentDisposition()) {
      con.disconnect();
      throw new PluginException(LinkStatus.ERROR_TEMPORARILY_UNAVAILABLE,10 * 60 * 1000l);
    }
    dl.startDownload();
  }
 else {
    Form form=br.getFormBySubmitvalue("String_Node_Str");
    if (form == null)     throw new PluginException(LinkStatus.ERROR_PLUGIN_DEFEKT);
    br.submitForm(form);
    if (br.containsHTML("String_Node_Str"))     throw new PluginException(LinkStatus.ERROR_TEMPORARILY_UNAVAILABLE,JDL.L("String_Node_Str","String_Node_Str"),10 * 60 * 1000l);
    String wait=br.getRegex("String_Node_Str").getMatch(0);
    if (wait != null)     throw new PluginException(LinkStatus.ERROR_IP_BLOCKED,Regex.getMilliSeconds(wait));
    if (br.containsHTML("String_Node_Str"))     throw new PluginException(LinkStatus.ERROR_IP_BLOCKED,null,2 * 60 * 1001l);
    if (br.getRedirectLocation() != null && br.getRedirectLocation().indexOf("String_Node_Str") > 0) {
      throw new PluginException(LinkStatus.ERROR_RETRY);
    }
    dllink=br.getRegex("String_Node_Str").getMatch(0);
    if (dllink == null)     throw new PluginException(LinkStatus.ERROR_PLUGIN_DEFEKT);
    dl=jd.plugins.BrowserAdapter.openDownload(br,downloadLink,dllink,true,1);
    URLConnectionAdapter con=dl.getConnection();
    if (Plugin.getFileNameFromHeader(con) == null || Plugin.getFileNameFromHeader(con).indexOf("String_Node_Str") >= 0) {
      con.disconnect();
      throw new PluginException(LinkStatus.ERROR_RETRY);
    }
    if (!con.isContentDisposition()) {
      con.disconnect();
      throw new PluginException(LinkStatus.ERROR_TEMPORARILY_UNAVAILABLE,10 * 60 * 1000l);
    }
    dl.startDownload();
  }
}