@Entity
    public static class User implements Serializable {
      private static final long serialVersionUID = 1l;
        @PrimaryKey
        @Sequence
        private Long identity;

        private String emailAdress;
        private String password;

        public Long getIdentity() {
          return PK;
        ...

    EntityStore store = new EntityStore(new File("bananadb"));
    store.open;

    PrimaryIndex<Long, User> users = store.getPrimaryIndex(Long.class, User.class);

    // optionally transactional
    // store.getTxn().begin();

    User user = new User();
    user.setEmailAdress("a@b.cd");
    user.setPassword("1");
    assertNull(user.getId());
    assertNull(store.put(user));
    assertNotNull(user.getId());

    user.setPassword("2");
    User oldUser = store.put(user);
    assertEquals("1", oldUser.getPassword());
    assertEquals("2", user.getPassword());

    // optionally transactional
    // store.getTxn().commit();