Parent parent = parentHome.create("parent");
ChildHome childHome = ChildUtil.getHome();
Child child = childHome.create( parent, "child");
GrandchildHome grandchildHome = GrandchildUtil.getHome();
// If you comment out the next line, then the call to child.remove() works fine.
grandchildHome.create(child.getId(), "grandchild");
// this is the test for non-null foreign key
child.remove();
}