//クエリ
@NamedQuery(
            name = "id_select",
            query = "SELECT rf.id FROM ReportFavo AS rf WHERE rf.report_id = :report_id AND rf.employee = :employee"
            )

//クエリの値を変数へ格納
int id = em.createNamedQuery("id_select" , int.class)
                .setParameter("report_id" , report_id)
                .setParameter("employee" , employee_id)
                .getSingleResult();

エラーメッセージ

HTTPステータス 500 - Type specified for TypedQuery [int] is incompatible with query return type [class java.lang.Integer]