Query.getSingleResult throw Exception

[javatwo]

I used the following way to check if Student 'John' exists in the Student table:

Student s = entityManager.createQuery("from Student s where s.name='John'").getSingleResult();

If John is not in the table, I got an EJBException:

Caused by: javax.ejb.EJBException: null; CausedByException is:
No entity found for query

I expect the method to return a NULL value if John is not in the table.
My question is: how to check if an entity(record) alreay exists?

Please help. Thanks!
Have a nice day.
P.S. I am using JBOSS AS 4.0.3RC1 on XP.

[epbernard]

This is as per the getSingleResult() JavaDoc.
Use

List result = entityManager.createQuery("from Student s where s.name='John'").getResultList();
if ( result.size() == 0 ) ...

[javatwo]

HI Emmanuel,
Thanks for reply.
I tried the code that you suggested, using getResultList() instead, but I still got the same exception.
If both methods throw exception in case of Entity not found, which exception should I catch?
Could you point me to the right javadoc? Thanks for help.

[javatwo]

I catch
EntityNotFoundException. Working well. Thanks.