Java tutorial
//package com.java2s; import java.util.regex.Matcher; import java.util.regex.Pattern; public class Main { public static final boolean isValidPassword(final String password) { boolean result = false; if (password != null) { Pattern pattern = Pattern .compile("^[\\@A-Za-z0-9\\!\\#\\$\\%\\^\\&\\*\\.\\~\\*\\(\\)\\+\\-\\=\\_]{6,20}$"); Matcher matcher = pattern.matcher(password.trim()); result = matcher.matches(); } return result; } }