public IBOOKProviderManager getBookProviderrManager() {
    return bookProviderManager;
}

public long getCoursesAddedByTP(Integer bookProviderId){
    return courseManager.getCoursesAddedByTP(bookProviderId);
}

public long getCoursesAddedByTP(Integer bookProviderId){

    Query query = this.em.createQuery(

    " SELECT COUNT(*) AS total FROM Courses c WHERE c.book_provider_id = " +bookProviderId);

    long coursesByTP = 0;

    try {
         coursesByTP = (Long) query.getSingleResult();
    } catch (Exception e) {
        e.getStackTrace();
    }

    return coursesByTP;
}

public long getCoursesAddedByTP(Integer bookProviderId){
    Query query = this.em.createQuery(
        "SELECT c FROM Courses c WHERE c.book_provider_id = :tpID");
    query.setParameter("tpID", bookProviderId);
    long coursesByTP = 0;
    try {
         coursesByTP = query.getResultList().size();  // getResultList() and not getSingleResult()
    } catch (Exception e) {
        e.getStackTrace();
    }
    return coursesByTP;
}