Merge function in jdbc - jdbc

Question

public static void merge() {
EntityManagerFactory emf = Persistence.createEntityManagerFactory("LifeCycle");
EntityManager em = null;
try {
em = emf.createEntityManager();
System.out.println("--------------------------------------------------------");
EmployeeEntity employee=new EmployeeEntity();
employee.setEmpId(1002);
//employee.setEmpId(1111);
employee.setEmpLocation("Mysore");
employee.setEmpName("Mahadeva");
System.out.println("Before merge : The EmployeeEntity instance is in MANAGED state :" + em.contains(employee));
em.merge(employee);
System.out.println("After merge : The EmployeeEntity instance is in MANAGED state :" + em.contains(employee));
em.getTransaction().begin();
em.getTransaction().commit();
System.out.println("After Commit : The EmployeeEntity instance is in MANAGED state :" + em.contains(employee));
System.out.println("--------------------------------------------------------");
} catch (Exception exception) {
System.out.println(exception.getMessage());
} finally {
if(em!=null){
em.close();
}
if (emf != null) {
emf.close();
}
}
}
For all three syso i get false as the output ,why? i don't understand, even when I write syso between begin() and commit then also it is giving false as the output.
thank you in advance.

Answer 1

Merge works on the clone of the entity .
It first copies the attributes of the clone into the unit of work copy and then that cloned entity is managed and not the original entity you passed.
What you are expecting in your example is for em.persist(entity) operation. persist registers the entity without cloning.
Try with em.persist(entity) and it should give you expected result.
merge operation is provided for RMI objects and hence that behavior.