Generate 6 digit 2fa codes in sync with Google Authenticator

GoogleAuthenticatorDemo.java

String secretKey = "quu6 ea2g horg md22 sn2y ku6v kisc kyag";
String lastCode = null;
while (true) {
    String code = getTOTPCode(secretKey);
    if (!code.equals(lastCode)) {
        // output a new 6 digit code
        System.out.println(code);
    }
    lastCode = code;
    try {
        Thread.sleep(1000);
    } catch (InterruptedException e) {};
}