private void setFailedSubEvents(String rawLog) {
    Set<String> failedSubEvents = new HashSet<String>();
    Matcher unsuccessfulMRTaskIdMatcher = _unsuccessfulMRTaskIdPattern.matcher(rawLog);
    while (unsuccessfulMRTaskIdMatcher.find()) {
      failedSubEvents.add(unsuccessfulMRTaskIdMatcher.group(1));
    }
    this._failedSubEvents = failedSubEvents;
  }
Given MR Job log, finds the list of unsuccessful tasks and sets it equal to _failedSubEvents
@param rawLog MR Job log in a string
app/com/linkedin/drelephant/exceptions/MRJobLogAnalyzer.java