Hello everyone,
In my application, I have some persistency objects (entity instances) which are loaded into memory and I use same instances throughout the lifecycle of the application. These objects can be modified by different threads and they are persisted into to the database with a code as follows:
Code:
public static <T> T updateEntity(T entity, long id) {
EntityManager em = null;
EntityTransaction tx = null;
try {
em = GenericPersistenceManager.emf.createEntityManager();
tx = em.getTransaction();
tx.begin();
entity = em.merge(entity);
tx.commit();
return entity;
} catch (RuntimeException e) {
if (tx.isActive()) {
tx.rollback();
}
throw e;
} finally {
em.close();
}
}
Sometimes when two threads try to update same object I get an exception as follows:
Code:
Caused by: com.mysql.jdbc.exceptions.jdbc4.MySQLIntegrityConstraintViolationException: Duplicate entry '1-6' for key 'PRIMARY'
I guess I'm getting this exception because of a concurrency issue. Because if I make the function abovesynchronized or if I run the threads one by one, I don't get the exception. So, what should I consider in this case? How can I handle this concurrency issue. I'm not so experienced in Hibernate. So, I will really appreciate your helps.
Thanks in advance
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