Validate Password

Check if a password meets basic strength rules using regex.

JavaIntermediate

Java

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

public class Main {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        System.out.print("Enter password: ");
        String pwd = sc.nextLine();

        // At least 8 chars, one digit, one lower, one upper
        String regex = "^(?=.*[0-9])(?=.*[a-z])(?=.*[A-Z]).{8,}$";
        boolean strong = Pattern.matches(regex, pwd);
        System.out.println(strong ? "Strong password" : "Weak password");
        sc.close();
    }
}

Output

Enter password: Abcdef1g
Strong password

We use lookahead-based regex to require digit, lowercase, uppercase, and minimum length.

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