Use GenerateRDSAuthToken with an AWS SDK

Use the RdsUtilities class to generate an authentication token.

public class GenerateRDSAuthToken {
    public static void main(String[] args) {
        final String usage = """

                Usage:
                    <dbInstanceIdentifier> <masterUsername>

                Where:
                    dbInstanceIdentifier - The database instance identifier.\s
                    masterUsername - The master user name.\s
                """;

        if (args.length != 2) {
            System.out.println(usage);
            System.exit(1);
        }

        String dbInstanceIdentifier = args[0];
        String masterUsername = args[1];
        Region region = Region.US_WEST_2;
        RdsClient rdsClient = RdsClient.builder()
                .region(region)
                .build();

        String token = getAuthToken(rdsClient, dbInstanceIdentifier, masterUsername);
        System.out.println("The token response is " + token);
    }

    public static String getAuthToken(RdsClient rdsClient, String dbInstanceIdentifier, String masterUsername) {

        RdsUtilities utilities = rdsClient.utilities();
        try {
            GenerateAuthenticationTokenRequest tokenRequest = GenerateAuthenticationTokenRequest.builder()
                    .credentialsProvider(ProfileCredentialsProvider.create())
                    .username(masterUsername)
                    .port(3306)
                    .hostname(dbInstanceIdentifier)
                    .build();

            return utilities.generateAuthenticationToken(tokenRequest);

        } catch (RdsException e) {
            System.out.println(e.getLocalizedMessage());
            System.exit(1);
        }
        return "";
    }
}