A utils for testing Password rule.

PasswordUtil.java

import java.util.regex.Pattern;

public class PasswordUtil {

    private static String MsgLen8 = "String Must be 8 characters long";
    private static String MsgUpper = "Must contain at least one upper case letter";
    private static String MsgLower = "Must contain at least one lower case letter";
    private static String MsgDigit = "Must contain at least one digit";
    private static String MsgSp = "Must contain at least one special character from this list: !@#$%^&*()+-.,\"'(){}[]:;?/\\";
    private static Pattern pattern = Pattern.compile("^(?=.*[0-9])(?=.*[a-z])(?=.*[A-Z])(?=.*[!@#$%^&*()+=])(?=\\\\S+$).{4,}$");
    private static Pattern UpperPt = Pattern.compile("(?=.*[A-Z])");
    private static Pattern LowerPt = Pattern.compile("(?=.*[a-z])");
    private static Pattern DigitPt = Pattern.compile("(?=.*\\d)");
    private static Pattern specialPt = Pattern.compile("[!@#$%&*()_+=|<>?{}\\[\\]~-]");
    static String msg = "Password must be at least 8 characters long. It must contain at least one upper-case letter, one lower-case letter, one number and one special character.";

    public static String IsStrong(String Password) {

        if (Password.length() < 8) {
            return msg;
        } else if (!UpperPt.matcher(Password).find()) {
            return msg;
        } else if (!LowerPt.matcher(Password).find()) {
            return msg;
        } else if (!DigitPt.matcher(Password).find()) {
            return msg;
        } else if (!specialPt.matcher(Password).find()) {

            return msg;
        } else {
            return "";
        }
    }
}