Java tutorial
//package com.java2s; import java.util.regex.Matcher; import java.util.regex.Pattern; public class Main { public static boolean isValidPassword(String password) { String PASSWORD_PATTERN = "((?=.*\\d)(?=.*[a-z])(?=.*[A-Z])(?=.*[@#$%]).{8,20})"; Pattern pattern = Pattern.compile(PASSWORD_PATTERN); Matcher matcher = pattern.matcher(password); return matcher.matches(); } }