@Entity

public class Point implements Serializable {

    private static final long serialVersionUID = 1L;

    @Id @GeneratedValue

    private long id;

    private int x;

    private int y;

    public Point() {

    }

    Point(int x, int y) {

        this.x = x;

        this.y = y;

    }

    public Long getId() {

        return id;

    }

    public int getX() {

         return x;

    }

    public int getY() {

         return y;

    }

    @Override

    public String toString() {

        return String.format("(%d, %d)", this.x, this.y);

    }

}

// Open a database connection

        // (create a new database if it doesn't exist yet):

        EntityManagerFactory emf =

            Persistence.createEntityManagerFactory("$objectdb/db/points.odb");

        EntityManager em = emf.createEntityManager();

        // Store 1000 Point objects in the database:

        em.getTransaction().begin();

        for (int i = 0; i < 1000; i++) {

            Point p = new Point(i, i);

            em.persist(p);

        }

        em.getTransaction().commit();

        // Find the number of Point objects in the database:

        Query q1 = em.createQuery("SELECT COUNT(p) FROM Point p");

        System.out.println("Total Points: " + q1.getSingleResult());

        // Find the average X value:

        Query q2 = em.createQuery("SELECT AVG(p.x) FROM Point p");

        System.out.println("Average X: " + q2.getSingleResult());

        // Retrieve all the Point objects from the database:

        TypedQuery<Point> query =

            em.createQuery("SELECT p FROM Point p", Point.class);

        List<Point> results = query.getResultList();

        for (Point p : results) {

            System.out.println(p);

        }

        // Close the database connection:

        em.close();

        emf.close();

Total Points: 1000

Average X: 499.5

(0,0)

(1,1)

(2,2)

(3,3)

 :

 :

(998,998)

(999,999)