Question

•Write a JAVA program to check a given password strength from a user's input.

•Create a method to check the number of characters. It must be more than 8.

•Create a method to check the password to have at least one uppercase letter.

•Create a method to check the password to have at least one lowercase letter.

•Create a method to check the password to have at least one digit.

•Create a method to check the password to have at least one special character (!, 2, #, %, &, *, (, ), etc.).

Answer 1

import java.util.Scanner;

public class PasswordValidate {

    public static boolean hasLength(String password) {
        return password.length() > 8;
    }

    public static boolean hasUppercase(String password) {
        for (int i = 0; i < password.length(); i++) {
            if (Character.isUpperCase(password.charAt(i)))
                return true;
        }
        return false;
    }

    public static boolean hasLowercase(String password) {
        for (int i = 0; i < password.length(); i++) {
            if (Character.isLowerCase(password.charAt(i)))
                return true;
        }
        return false;
    }

    public static boolean hasDigit(String password) {
        for (int i = 0; i < password.length(); i++) {
            if (Character.isDigit(password.charAt(i)))
                return true;
        }
        return false;
    }

    public static boolean hasSpecial(String password) {
        for (int i = 0; i < password.length(); i++) {
            if ("!@#%$%^&*()".contains("" + password.charAt(i)))
                return true;
        }
        return false;
    }

    public static void main(String[] args) {
        Scanner in = new Scanner(System.in);
        System.out.print("Enter password: ");
        String password = in.next();
        if (hasLength(password) && hasLowercase(password) && hasUppercase(password) && hasDigit(password) && hasSpecial(password)) {
            System.out.println(password + " is valid");
        } else {
            System.out.println(password + " is invalid");
        }
    }
}