Method to allow for query on DataAccess

DataAccess.java

protected List<T> queryString(String sql){
        EntityManagerFactory factory = Persistence.createEntityManagerFactory("JPAIntroduction");
        EntityManager em = factory.createEntityManager();
        List<T> results= em.createQuery(sql).getResultList();
        em.close();
        factory.close();
        return results;
    }