06. Validate Password

package Uprajneniq;

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

public class ValidatePassword {
    public static void main(String[] args) {
        Scanner scanner = new Scanner(System.in);

        int n = Integer.parseInt(scanner.nextLine());

        Pattern pattern = Pattern.compile("_\\.+(?<passwordText>[A-Z][A-Za-z0-9]{4,}[A-Z])_\\.+");

        for (int i = 0; i < n; i++) {
            String password = scanner.nextLine();
            Matcher matcher = pattern.matcher(password);

            if (matcher.matches()) {
                String passwordContent = matcher.group("passwordText");
                String group = extractGroup(passwordContent);
                System.out.println("Group: " + group);
            } else {
                System.out.println("Invalid pass!");
            }
        }
    }

    private static String extractGroup(String password) {
        StringBuilder groupBuilder = new StringBuilder();
        for (char c : password.toCharArray()) {
            if (Character.isDigit(c)) {
                groupBuilder.append(c);
            }
        }
        return groupBuilder.length() > 0 ? groupBuilder.toString() : "default";
    }
}