@Entity(name = "Event")
@Immutable
public static class Event {

	@Id
	private Long id;

	@Temporal(TemporalType.TIMESTAMP)
	@Column(name = "created_on")
	private Date createdOn = new Date();

	@Column(name = "event_key")
	private String eventKey;

	@Column(name = "event_value")
	private String eventValue;

	public Event(Long id, String eventKey, String eventValue) {
		this.id = id;
		this.eventKey = eventKey;
		this.eventValue = eventValue;
	}

	private Event() {
	}

	public Long getId() {
		return id;
	}

	public Date getCreatedOn() {
		return createdOn;
	}

	public String getEventKey() {
		return eventKey;
	}

	public String getEventValue() {
		return eventValue;
	}
}

entityManager.createQuery(
	"update Event " +
	"set eventValue = :eventValue " +
	"where id = :id")
.setParameter("eventValue", "10")
.setParameter("id", 1L)
.executeUpdate();