code: public static int indexOfIgnoreCase(final String source, final String target) {
  
      int targetIndex = source.indexOf(target);
      if (targetIndex == INDEX_OF_NOT_FOUND) {
        String sourceLowerCase = source.toLowerCase();
        String targetLowerCase = target.toLowerCase();
        targetIndex = sourceLowerCase.indexOf(targetLowerCase);
        return targetIndex;
      } else {
        return targetIndex;
      }
    }
docs: Returns the index within given source string of the first occurrence of the
  specified target string with ignore case sensitive.
  
  @param source source string to be tested.
  @param target target string to be tested.
  @return index number if found, -1 otherwise.