How to fix the Hibernate “object references an unsaved transient instance - save the transient instance before flushing” error

Question

I receive following error when I save the object using Hibernate

object references an unsaved transient instance - save the transient instance before flushi         


        

Answer 1

Don't use Cascade.All until you really have to. Role and Permission have bidirectional manyToMany relation. Then the following code would work fine

    Permission p = new Permission();
    p.setName("help");
    Permission p2 = new Permission();
    p2.setName("self_info");
    p = (Permission)crudRepository.save(p); // returned p has id filled in.
    p2 = (Permission)crudRepository.save(p2); // so does p2.
    Role role = new Role();
    role.setAvailable(true);
    role.setDescription("a test role");
    role.setRole("admin");
    List pList = new ArrayList();
    pList.add(p);
    pList.add(p2);
    role.setPermissions(pList);
    crudRepository.save(role);

while if the object is just a "new" one, then it would throw the same error.