Java example of oauth with refresh tokens

We have created a method the does the oauth authentication but it will not persist. Can anyone give me a Java example of one? Here is what I have so far.

@Bean(name="ring-central-rest-config")

public RestClient buildRingCentralRestClientUrl() {

RestClient rc = new RestClient(ringCentralClientId, ringCentralClientSecret, ringCentralServerUrl, getOkHttpClient(this.env));

try {

rc.authorize(accountId, extension, password);

}

catch (IOException | RestException e) {

logger.info("error in calling ring central rest client" + e.getMessage());

}

return rc;

}