gistfile1.txt

MongoClient client = MongoClients.create(MongoClientSettings.builder()
        .clusterSettings(ClusterSettings.builder().hosts(Collections.singletonList(new ServerAddress("localhost"))).build())
        .writeConcern(WriteConcern.UNACKNOWLEDGED).build());

System.out.println(client.getSettings().getWriteConcern());

client.getDatabase("test").getCollection("writeConcernTest").insertOne(new Document(), (result, t) -> System.out.println("DONE!"));

Thread.sleep(Long.MAX_VALUE);