code: private static boolean stringNumeric(int fieldWidth,
                                           int anotherFieldWidth,
                                           char patternLetter) {
          if ( patternLetter == 'M' ) {
              if ( fieldWidth <= 2 && anotherFieldWidth > 2 ||
                   fieldWidth > 2 && anotherFieldWidth <= 2 ) {
                  return true;
              }
          }
          return false;
      }
docs: /*
  Check whether one field width is numeric while the other is string.
  
  TODO (xji): make it general
  
  @param fieldWidth          one field width
  @param anotherFieldWidth   another field width
  @param patternLetter       pattern letter char
  @return true if one field width is numeric and the other is string,
  false otherwise.