Java tutorial
//package com.java2s; import java.util.regex.Matcher; import java.util.regex.Pattern; public class Main { public static boolean isPasswordStronger(String password) { String string = "^(?:(?=.*[A-Z])(?=.*[a-z])(?=.*[0-9])|(?=.*[A-Z])(?=.*[a-z])(?=.*[^A-Za-z0-9])|(?=.*[A-Z])(?=.*[0-9])(?=.*[^A-Za-z0-9])|(?=.*[a-z])(?=.*[0-9])(?=.*[^A-Za-z0-9])).{6,}|(?:(?=.*[A-Z])(?=.*[a-z])|(?=.*[A-Z])(?=.*[0-9])|(?=.*[A-Z])(?=.*[^A-Za-z0-9])|(?=.*[a-z])(?=.*[0-9])|(?=.*[a-z])(?=.*[^A-Za-z0-9])|(?=.*[0-9])(?=.*[^A-Za-z0-9])|).{8,}"; Pattern p = Pattern.compile(string); Matcher m = p.matcher(password); return m.matches(); } }