Java tutorial
//package com.java2s; //License from project: Apache License public class Main { public static String getOnlyNumerics(String input) { if (input == null) return null; StringBuilder strBuff = new StringBuilder(); for (int i = 0; i < input.length(); i++) { char c = input.charAt(i); if (Character.isDigit(c)) strBuff.append(c); } return strBuff.toString(); } }