Question

Having a secure password is a very important practice, when much of our information is stored online. Write a program that validates a new password, following these rules:

•The password must be at least 8 characters long.

•The password must have at least one uppercase and one lowercase letter

•The password must have at least one digit.

Write a program that asks for a password, then asks again to confirm it. If the passwords don’t match or the rules are not fulfilled, prompt again. Your program should include a method that checks whether a password is valid.

In java 1.7

Answer 1

Console Based Password Validation Program :

package Library;

import java.util.Scanner;
import java.util.regex.Matcher;
import java.util.regex.Pattern;

public class ValidatePassword {

   public static void main(String[] args) {
      
       Scanner sc = new Scanner(System.in);
  
       boolean isNotValid = true;
       while(isNotValid) {
           System.out.println("Enter Password : ");
           String pwd = sc.nextLine();
          
           System.out.println("Confirm Password : ");
           String cPwd = sc.nextLine();
          
           if(!isValidPassword(pwd)) {
               isNotValid = true;
               System.out.println("Your password doesn't match the criteria of a valid paasword");
           }
           else if(!confirmPassword(pwd, cPwd)) {
               isNotValid = true;
               System.out.println("Your password and Confirmed password does not match.");
           }else {
               isNotValid = false;
               break;
           }
       }
      
       System.out.println("Password created successfully.");
      

   }
  
   public static boolean
isValidPassword(String password)
{
  
// Regex to check valid password.
String regex = "^(?=.*[0-9])"//represents a digit must occur at least once
+ "(?=.*[a-z])(?=.*[A-Z])"//) represents a lower and upper case alphabet must occur at least once.
+ "(?=\\S+$).{8,}$"; //represents at least 8 characters
  
// Compile the ReGex
Pattern p = Pattern.compile(regex);
  
// If the password is empty
// return false
if (password == null) {
return false;
}
  
// Pattern class contains matcher() method
// to find matching between given password
// and regular expression.
Matcher m = p.matcher(password); //Matches the given string with the Regex
  
// Return if the password
// matched the ReGex
return m.matches();
}
  
   public static boolean confirmPassword(String pwd, String cPwd) {
       if(pwd.equals(cPwd)) return true;
       else return false;
   }
  

}