PasswordGenerator.java

import java.security.SecureRandom;

public class PasswordGenerator {

    private static final String UPPERCASE_LETTERS = "ABCDEFGHIJKLMNOPQRSTUVWXYZ";
    private static final String LOWERCASE_LETTERS = "abcdefghijklmnopqrstuvwxyz";
    private static final String DIGITS = "0123456789";
    private static final String SPECIAL_CHARACTERS = "!@#$%^&*()-_+=<>?";

    private static final String ALL_CHARACTERS = UPPERCASE_LETTERS + LOWERCASE_LETTERS + DIGITS + SPECIAL_CHARACTERS;
    private static final SecureRandom random = new SecureRandom();

    public static String generatePassword(int length) {
        if (length < 1) throw new IllegalArgumentException("Password length must be greater than 0");

        StringBuilder password = new StringBuilder(length);

        // Ensure the password has at least one character from each character set
        password.append(UPPERCASE_LETTERS.charAt(random.nextInt(UPPERCASE_LETTERS.length())));
        password.append(LOWERCASE_LETTERS.charAt(random.nextInt(LOWERCASE_LETTERS.length())));
        password.append(DIGITS.charAt(random.nextInt(DIGITS.length())));
        password.append(SPECIAL_CHARACTERS.charAt(random.nextInt(SPECIAL_CHARACTERS.length())));

        // Fill the remaining characters randomly from all characters
        for (int i = 4; i < length; i++) {
            password.append(ALL_CHARACTERS.charAt(random.nextInt(ALL_CHARACTERS.length())));
        }

        // Shuffle the password to ensure randomness
        char[] passwordArray = password.toString().toCharArray();
        for (int i = 0; i < passwordArray.length; i++) {
            int randomIndex = random.nextInt(passwordArray.length);
            char temp = passwordArray[i];
            passwordArray[i] = passwordArray[randomIndex];
            passwordArray[randomIndex] = temp;
        }

        return new String(passwordArray);
    }

    public static void main(String[] args) {
        int passwordLength = 12; // You can set this to any length you want
        String password = generatePassword(passwordLength);
        System.out.println("Generated Password: " + password);
    }
}