How to check if a record exists using JPA

If you just want to know whether the object exists, send a SELECT COUNT to your database. That will return 0 or 1.

The cost of the exception handling isn't that big (unless you do that millions of times during a normal operation), so I wouldn't bother.

But the code doesn't really reflect your intention. Since getSingleResult() calls getResultList() internally, it's clearer like so:

public boolean objExists(...) {
    return getResultList(...).size() == 1;
}

If you query by object id and you have caching enabled, that will become a simple lookup in the cache if the object has already been loaded.

Simply use count(e) in your query, so no NoResultException will be thrown and you will avoid loading the entity object
So the Java code can be as follow:

public boolean isRecordExist() {
    String query = "select count(e) from YOUR_ENTITY e where ....";
    // you will always get a single result
    Long count = (Long) entityManager.createQuery( query ).getSingleResult();
    return ( ( count.equals( 0L ) ) ? false : true );
}

Hope that helps someone :)

If you are searching by primary key you can also use Entitymanger.find(entityClass, primaryKey) which returns null when the entity does not exist.

Try to avoid loading the entity into the session (getSingleResult()) just to check for it's existence. A count is better here. With the Criteria Query API it would look something like this:

public <E extends AbstractEntity> boolean exists(final Class<E> entityClass, final int id) {
    final EntityManager em = getEntityManager();
    final CriteriaBuilder cb = em.getCriteriaBuilder();

    final CriteriaQuery<Long> cq = cb.createQuery(Long.class);
    final Root<E> from = cq.from(entityClass);

    cq.select(cb.count(from));
    cq.where(cb.equal(from.get(AbstractEntity_.id), id));

    final TypedQuery<Long> tq = em.createQuery(cq);
    return tq.getSingleResult() > 0;
}