Java Driver

Create a tailable cursor

find(query).projection(fields).cursorType(CursorType.TailableAwait).iterator();

That code applies to the MongoCollection class.

CursorType is an enum and it has the following values:

Tailable
TailableAwait

Corresponding to the old (<3.0) DBCursor addOption Bytes types:

Bytes.QUERYOPTION_TAILABLE
Bytes.QUERYOPTION_AWAITDATA

Create a database user

To create a user dev with password password123

MongoClient mongo = new MongoClient("localhost", 27017);
MongoDatabase db =  mongo.getDatabase("testDB");
Map<String, Object> commandArguments = new BasicDBObject();
commandArguments.put("createUser", "dev");
commandArguments.put("pwd", "password123");
String[] roles = { "readWrite" };
commandArguments.put("roles", roles);
BasicDBObject command = new BasicDBObject(commandArguments);
db.runCommand(command);

Fetch Collection data with condition

To get data from testcollection collection in testdb database where name=dev

import org.bson.Document;
import com.mongodb.BasicDBObject;
import com.mongodb.MongoClient;
import com.mongodb.ServerAddress;
import com.mongodb.client.MongoCollection;
import com.mongodb.client.MongoCursor;
import com.mongodb.client.MongoDatabase;

MongoClient mongoClient = new MongoClient(new ServerAddress("localhost", 27017));
MongoDatabase db = mongoClient.getDatabase("testdb");
MongoCollection<Document> collection = db.getCollection("testcollection");

BasicDBObject searchQuery = new BasicDBObject();
searchQuery.put("name","dev");

MongoCursor<Document> cursor = collection.find(searchQuery).iterator();  
try {
    while (cursor.hasNext()) {
        System.out.println(cursor.next().toJson());
    }
} finally {
    cursor.close();
}