Why does Axon.ivy issue a lot of warning message of "Entity manager will be closed now."

When you create a hibernate EntityManager you should also close its instance when the EntityManager is no longer used. This must be done as else every EntityManager will hold and keep a connection from the connection pool and this can lead to a leak.

To prevent a connection leak the ivy core now closes all open EntityManager instances on HttpRequestEnd. If a not correctly closed instance is found, we log the warning you mentioned.

To avoid the warning you should correctly close open EntityManager instances. Best practice is to handle EntityManager.close() in a finally block:

private static List querySomething(){
    IIvyEntityManager ivyEntityManager = Ivy.persistence().get("myPersistencUnitName");
    EntityManager em = ivyEntityManager.createEntityManager();
    try{
        em.getTransaction().begin();
        List results = em.createQuery("SELECT XXX").getResultList();
        em.getTransaction().commit();
        return results;
    } finally {
        em.close();
    }
}