code: private int getExceptionLine() {
      for (int i = 0; i < additionalLines.size(); i++) {
        Matcher exceptionMatcher = exceptionPattern.matcher((String)additionalLines.get(i));
        if (exceptionMatcher.matches()) {
          return i;
        }
      }
      return -1;
    }
docs: Walk the additionalLines list, looking for the EXCEPTION_PATTERN.
  <p>
  Return the index of the first matched line
  (the match may be the 1st line of an exception)
  <p>
  Assumptions: <br>
  - the additionalLines list may contain both message and exception lines<br>
  - message lines are added to the additionalLines list and then
  exception lines (all message lines occur in the list prior to all
  exception lines)
  
  @return -1 if no exception line exists, line number otherwise