Java development with MongoDB
To access a MongoDB database from a Java program, you must first download the mongo-java-driver JAR files. You can get them from here:
http://central.maven.org/maven2/org/mongodb/mongo-java-driver/
Choose a recent, stable version; like, 3.4.2. Download the two JAR files: mongo-java-driver-3.4.2.jar and mongo-java-driver-3.4.2-javadoc.jar.
The program in Listing 10-2 shows how to use Java to access a Mongo database, in this case our friends database:

Listing 10-2. Java program to print collection documents
At lines 18-20, we instantiate the three objects necessary to access our relatives collection: a MongoClient object, a MongoDatabase object, and a MongoCollection object. The rest of the program iterated through all the documents in that collection, numbering and printing them in alphabetical order.
Line 23 instantiates a specialized Iterable object that uses the find() method on the relatives collection, accessing its documents according to the ordering specified...