public class TestHibernate extends TestCase {

    @Entity
    public static class Label {
        @Id
        @GeneratedValue
        long id;

        String label = "";

        @Override
        public int hashCode() {
            return this.label == null ? 0 : this.label.hashCode();
        }

        @Override
        public boolean equals(Object obj) {
            final Label other = (Label) obj;
            return this.label == null ? other.label == null : this.label.equals(other.label);
        }
    }

    @Entity
    public static class Assoc {
        @Id
        @GeneratedValue
        long id;

        @ManyToOne(cascade = CascadeType.ALL)
        Label label;

    }

    @Entity
    public static class Container {
        @Id
        @GeneratedValue
        long id;

        @OneToMany(cascade = CascadeType.ALL)
        @MapKey(name = "label")
        Map<Label, Assoc> map = new HashMap<Label, Assoc>();

    }

    public void testSimple() throws Exception {
        AnnotationConfiguration cfg = new AnnotationConfiguration();
        cfg.setProperty(Environment.DIALECT, HSQLDialect.class.getName());
        String driver = jdbcDriver.class.getName();
        cfg.setProperty(Environment.DRIVER, driver);
        String url = "jdbc:hsqldb:target/test_db.model;shutdown=true;sql.enforce_strict_size=true";
        cfg.setProperty(Environment.URL, url);
        cfg.setProperty(Environment.USER, "sa");
        cfg.setProperty(Environment.HBM2DDL_AUTO, "create-drop");
        cfg.addAnnotatedClass(Container.class);
        cfg.addAnnotatedClass(Label.class);
        cfg.addAnnotatedClass(Assoc.class);
        SessionFactory sessionFactory = cfg.buildSessionFactory();
        Session session = sessionFactory.openSession();
        Container c = new Container();
        Label l = new Label();
        l.label = "someLabel";
        Assoc s = new Assoc();
        s.label = l;
        c.map.put(l, s);
        session.save(c);
        session.flush();
        session.clear();
        Container c1 = (Container) session.get(Container.class, c.id);
        assertNotNull(c1);
        assertNotNull(c1.map);
        Assoc next = c1.map.values().iterator().next();
        assertNotNull(next);
        assertNotNull(next.label);
        assertNotNull(next.label.label);
        assertEquals(l.label, next.label.label);
        assertNotNull(c1.map.get(next.label));
    }