private int getExceptionLine(ParsingContext ctx) {
    String[] additionalLines = ctx.getUnmatchedLog().toString().split("\n");
    for (int i = 0; i < additionalLines.length; i++) {
      Matcher exceptionMatcher = exceptionPattern.matcher(additionalLines[i]);
      if (exceptionMatcher.matches()) {
        return i;
      }
    }
    return -1;
  }
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
olv-core/src/main/java/pl/otros/logview/parser/log4j/Log4jPatternMultilineLogParser.java