public T inserir(T entity) throws Exception {
    try {
        manager.getTransaction().begin();
        manager.persist(entity);
        manager.getTransaction().commit();
    } catch (Exception e) {
        manager.getTransaction().rollback();
    }
    return entity;
}`

public void excluir(T entity) {
    try {
        manager.getTransaction().begin();
        manager.remove(entity);
        manager.getTransaction().commit();
    } catch (Exception e) {
        manager.getTransaction().rollback();
    }
}

public Item inserir(Item item){
    try {
        return geralDAO.inserir(item);
    } catch (Exception e) {
        System.err.println(e.getMessage());
        return null;
    }
}

public void excluir(Item item){
    try {
        geralDAO.excluir(item);

    } catch (Exception e) {
        System.err.println("Erro ao deletar", e.getMessage());
    }
}

public void setProdutos(ProdutosVO produto) throws Exception{
    try {
        EntityManagerFactory factory = Persistence.createEntityManagerFactory("model");
        EntityManager manager = factory.createEntityManager();

        manager.getTransaction().begin();
        manager.persist(produto);
        manager.getTransaction().commit();

    } catch (Exception e) {
        throw new Exception(e);
    }finally {
        manager.close();
        factory.close();
    }
}