code: public static String getJobDetailsHistoryLink(JobTracker tracker,
                                                  String jobId) {
      RetireJobInfo info = tracker.retireJobs.get(JobID.forName(jobId));
      String historyFileUrl = getHistoryFileUrl(info);
      String result =  (historyFileUrl == null ? "" :
                "jobdetailshistory.jsp?jobid=" + jobId + "&logFile=" +
                historyFileUrl);
      return result;
    }
docs: Given jobId, resolve the link to jobdetailshistory.jsp
  @param tracker JobTracker
  @param jobId JobID
  @return the link to the page jobdetailshistory.jsp for the job