Provide code samples for MongoDB 3.6 page

// 1. The database for reactive, real-time applications

MongoClient mongoClient;

// Create a new MongoClient with a MongoDB URI string.

if (args.length == 0) {

// Defaults to a localhost replicaset on ports: 27017, 27018, 27019

  mongoClient = new MongoClient(new

  MongoClientURI("mongodb://localhost:27017,localhost:27018,localhost:27019"));

} else {

  mongoClient = new MongoClient(new MongoClientURI(args[0]));

}

// Select the MongoDB database.

MongoDatabase database = mongoClient.getDatabase("testChangeStreams");

// Select the collection to query.

MongoCollection<Document> collection = database.getCollection("documents");

// Create the change stream cursor.

MongoCursor<Document> cursor = collection.watch().iterator();

// 2. Tunable consistency controls

String connectionString = "mongodb://localhost/?readPreference=secondaryPreferred";

MongoClient client = new MongoClient(new MongoClientURI(connectionString);

MongoDatabase database = client.getDatabase("myDatabase");

MongoCollection<Document> collection = database.getCollection("myCollection");

// Start client session, which is causally consistent by default

try (ClientSession session = client.startSession(ClientSessionOptions.builder().build())) {

  //Run causally related operations within the session

  collection.insertOne(session, ...);

  collection.updateOne(session, ...);

  try (MongoCursor<Document> cursor = collection.find(session).filter(...).iterator()) {

    while (cursor.hasNext()) {

      Document cur = cursor.next();

    }

  }

}

// 3. Exploiting the power of arrays

MongoCollection<Document> collection = client

  .getDatabase("test")

  .getCollection("arrayUpdatesTest");

collection.updateOne(

  Filters.eq("_id", 1),

  Updates.set("a.$[i].b", 2),

new UpdateOptions()

  .arrayFilters(

    Collections.singletonList(

      Filters.eq("i.b", 0))));