Multiple updates to the same entity

Question

I have a Hibernate related question . Can I perform multiple saves to a single entity . Do you foresee any problems with this code?

// I create a new object of type Payment that needs to be persisted...

 Payment p1 = new Payment();

//Set some values..

 p1.setName("abc");

//persist it to DB to retrieve the Id which is autogenerated inorder to relay it to another function..

 Payment savedP1 = paymentRepository.save(p1);

 int sum = calPaymentSum(savedP1.getId());

//set more values to the same object ...

 savedP1.setSum(sum);

//update that object that was saved to DB earlier..

 paymentRepository.save(savedP1);

Answer 1

You need to use;

 paymentRepository.update(savedP1);

If you use save method, it is inserted to table with new id.

Answer 2

If you are using spring data jpa repository saving an existing entity will automatically update it and your procedure is right. but in javaEE jpa you need to use merge method of EntityManager in order to update an existing entity.

paymentRepository.merge(savedP1);