why does hibernate try mislay i try update/insert?

in app i have hibernate-mapped forms (general case):

class rolerule {
  private purpose role;
  private permissionawareentity entity; // hibernate-mapped entity assent granted
  private permissiontype permissiontype; // enum

  @manytoone
  @joincolumn(name = "role_id")
  open purpose getrole() {
    relapse role;
  }
  open vacant setrole(role role) {
    this.role = role;
  }

}

class purpose {
  private set<rolerule> manners = new hashset<rolerule>(0);

  @onetomany(cascade=cascadetype.all)
  @joincolumn(name="role_id")
  open set<rolerule> getrules() {
    relapse rules;
  }
  open vacant setrules(set<rolerule> rules) {
    this.rules = rules;
  }

}

all classes have equals() & hashcode() overrides.

my concentration allows tweaking roles (by sysadmins only, don't worry), among fields, allows origination new purpose rules. new order combined i try emanate new rolerule vigilant insert role's domain rules. i session.update(role) ask changes database.

now comes dizzy part... hibernate decides following shutting transaction flushing:

1. insert new order database. excellent.


2. update purpose fields (not collections). distant good.


3. update existent rules, even zero altered them. i live this.


4. update existent manners again. here's brew log, including involuntary comment:
   

/* mislay one-to-many quarrel role.rules */
update role_rule set role_id=null where role_id=? role_rule_id=?

of course, fields not-null, operation fails spectacularly.

can anyone try explain since hibernate this??? even some-more important, frak i around this???

edit: i certain something mapping, following boss, whim, deleted equals() hashcode() both classes, recreated controlling eclipse, mysteriously solved problem.

i'm still unequivocally extraordinary doubt though. anyone advise since hibernate this?