Coding style and best practice regarding exception-handling
The way you are handling the exception will result in the method returning normally whether or not the method has succeeded.  This is bad API design.  Better design would be to either return some special value to indicate failure or (better) to allow the exception to propagate, or throw a different one.

Catching Exception is usually a bad idea.  The problem is that you may end up catching all sorts of unexpected exceptions.

Unconditionally writing stacktraces to standard output is bad practice.  Use a logging system; e.g. java.util.logging, log4j, etcetera.

Here is an alternative version that avoids these problems:

public Comics add(Comics comics) throws ... {
    EntityManager em = EMF.get().createEntityManager();
    EntityTransaction tx = null;
    try {
        tx = em.getTransaction();
        tx.begin();
        em.persist(comics);
        tx.commit();
    } finally {
        try {
            if (tx != null &amp;&amp; tx.isActive()) {
                tx.rollback();
            }
        } finally {
            em.close();
        }
    }
    return comics; 
}