A sample class showing basic usage of the MongoDB Java driver.

MongoDBTest.java

import com.mongodb.MongoClient;
import com.mongodb.DB;
import com.mongodb.DBCollection;
import com.mongodb.BasicDBObject;
import com.mongodb.DBObject;
import com.mongodb.DBCursor;
import java.net.UnknownHostException;
import java.util.ArrayList;
import java.util.Set;

public class MongoDBTest {
    
	public static MongoClient mongoClient;
	public static DB db;
	
	public static void main(String[] args) {

		try { // Open a new connection
			mongoClient = new MongoClient("localhost", 27017);
			db = mongoClient.getDB("users");
		}  catch (UnknownHostException e) {
			e.printStackTrace();
		}
		
		// Print out all the collections in the users database
		System.out.println("Printing all collections..."); 
		Set<String> colls = db.getCollectionNames();
		for (String s : colls) { System.out.println(s); } 
		
		// Get the casey collection
		DBCollection coll = db.getCollection("casey");
		
		// Create a new document
		System.out.println("\nAdding document to database..."); 
		ArrayList<String> languages = new ArrayList<>();
		languages.add("Ruby");
		languages.add("Java");
		languages.add("Groovy");
		
		BasicDBObject doc = new BasicDBObject("name", "Casey Scarborough").
				append("age", 22).
				append("email", "caseyscarborough@gmail.com").
				append("languages", languages);
		
		// Insert the document into the collection
		coll.insert(doc);
		
		// Retrieve the first document in the collection
		System.out.println("Retrieving document from database..."); 
		DBObject myDoc = coll.findOne();
		System.out.println(myDoc);
		
		// Retrieve all documents from the collection
		DBCursor cursor = coll.find();
		
		try { // Use a cursor to get all documents.
			while(cursor.hasNext()) {
				System.out.println(cursor.next()); 
			}
		} finally { 
			cursor.close();
		}
		
		// Retrieve a document using a query.
		BasicDBObject query = new BasicDBObject("name", "Casey Scarborough");
		cursor = coll.find(query);
		
		System.out.println("\nPrinting query results..."); 
		// Print each result.
		try {
			while(cursor.hasNext()) {
				System.out.println(cursor.next()); 
			}
		} finally {
			cursor.close();
		}
		
		// Get a list of databases.
		System.out.println("\nPrinting a list of databases..."); 
		try {
			mongoClient = new MongoClient();
		} catch (UnknownHostException e) {
			e.printStackTrace();
		}
		
		for (String s : mongoClient.getDatabaseNames()) {
			System.out.println(s); 
		}
	}
}