How to authenticate mongo db using java driver [duplicate]

The Java MongoDB driver documentation says creating mongoclient will perform authentication, but it will never happened.

Here's my sample code:

new MongoClient(serverAddr, 
                Arrays.asList(credential), 
                new MongoClientOptions.Builder()
                                     .socketKeepAlive(true)
                                     .socketTimeout(30000)
                                     .build());