Here you can find the source of minus(String second, String first)
private static String minus(String second, String first)
//package com.java2s; //License from project: Open Source License public class Main { private static String minus(String second, String first) { try {//w w w . j a v a 2s . com return String.valueOf(Integer.parseInt(first) - Integer.parseInt(second)); } catch (NumberFormatException e) { try { return String.valueOf(Double.parseDouble(first) - Double.parseDouble(second)); } catch (NumberFormatException e2) { throw new IllegalArgumentException(first + " - " + second); } } } }