Mine

 public static List EXPGetListByENLDevancier(String enl) {
        EntityManagerFactory emf = Database.getInstance().getEmf();
        EntityManager em = emf.createEntityManager();
        
        Query q = em.createQuery("select b from EXP b where b.ENLDevancier = :enl");
        q.setParameter("enl", enl);
        List<EXP> p = q.getResultList();
        return p;
    }    
    
    public static List ContratGetListByClientId(int id) {
        EntityManagerFactory emf = Database.getInstance().getEmf();
        EntityManager em = emf.createEntityManager();
        
        Query q = em.createQuery("select b from Contrat b where b.client.id = :id");
        q.setParameter("id", id);
        List<Contrat> p = q.getResultList();
        return p;
    }