Defines JPA behavior for setting same value again?

Question

I wonder, if there is any definition by JPA for the behavior, if you setting equals value for any property. I didn't find any words in the specification.

I've tested with TopLink Essentials and Hibernate, what happens if I load a entity from database and set the property with same value again.

@Entity
public class MyEntity {
  @Id
  @GeneratedValue(strategy = GenerationType.IDENTITY)
  private Integer id;

  @Column(length = 20)
  private String value;

  @Version
  private long version;

  // Define setter and getter...
}

Setting the same value with

entity.setValue(new String(myChars));

does not change the version value.

Can I expect this behavior for every implementation. I don't think so...

Answer 1

So you set the value to the same thing, so it hasn't changed, so why should anything happen ? DataNucleus won't change anything ... since nothing has changed. QED