Question

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

    private int salary;

    @Version
    private long version;

    // ...getters and setters
}

Is it required to create setter/getter for version?
When persisting this entity with Hibernate, I don t need to set this value manually, right?
What else do I need to configure in order to use optimistic concurrency checking with Spring s hibernateTemplate.saveOrUpdate? Are all databases supported?
How to unit-test this entity? In my database all my records showing version field have value of 0
Will calling hibernateTemplate.saveOrUpdate increment the version value every time?

Answer 1

I would say:

set/get version is required, as you might assign the version yourself sometimes (when recreating an new instance from old data)
You don t need if you read the instance from the database. (When creating it in your code with new, it would be a different story).
I see nothing else. I never had a problem with a database.
Unit test don t go the database in my opinion, so tests involving the database are called integration tests. You shouldn t have too much of them, as they are slow, and they don t really test your code, but more the Hibernate/Driver/Database codes ... You should trust them, or just test them once, but not for all your entities.
To see version values more than 0, read/modify/update your entity in a transaction, the version increase by one. Go out of the transaction, do it again, the value increases ...
The version will increase each time the database row is modified.

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