}
c = (Category) s.load(Category.class, id);
c.getSubcategories().size(); //force load
Session ss = openSession();
Category c2 = (Category) ss.load(Category.class, id);
ss.delete( c2.getSubcategories().get(0) );
c2.getSubcategories().clear();
ss.flush();
ss.connection().commit();
ss.close();