code: public static final Parser<Integer> instance() { // NOPMD it's thread save!
      if (IntegerParserWithoutSeparator.instanceParser == null) {
        synchronized (IntegerParserWithoutSeparator.class) {
          if (IntegerParserWithoutSeparator.instanceParser == null) {
            IntegerParserWithoutSeparator.instanceParser = new IntegerParserWithoutSeparator();
          }
        }
      }
      return IntegerParserWithoutSeparator.instanceParser;
    }
docs: returns the instance.
  
  @return IntegerParserWithoutSeparator