Hibernate : Fetch collection -

i encontered problem while trying collection of elements : set of friend empty.

there 3 classes :

@entity @table(name="user") public class user { @id @column(name="user_id", nullable=false)  private string mail;  @column(name="password") private string password;  @column(name="surname") private string surname;  @column(name="name") private string name = null;  @column(name="statut") private statutuser statut;  @column(name="phonenumber") private int phonenumber;  @onetomany(cascade = cascadetype.persist, mappedby="friendpk.friend") @fetch(fetchmode.join)     private set<friend> friends = new hashset<friend>();      ...      getters , setters 

the second 1 :

@entity @table(name = "friend") public class friend {  @embeddedid  public friendpk friendpk;  @column(name = "friend_statut") private statutfriend statutfriend;  ...  } 

the last 1 :

@suppresswarnings("serial") @embeddable  public class friendpk implements serializable{      @manytoone     @joincolumn(name="user1_id", referencedcolumnname="user_id")     protected user user1;      @manytoone     @joincolumn(name="user2_id", referencedcolumnname="user_id")     protected user friend; } 

when try friends' user, collection empty.

here's file method add relationship :

private entitymanagerfactory emf; private entitymanager manager;  public string addfriends(string mail1, string mail2){          entitytransaction t;         t = manager.gettransaction();          try{             t.begin();              user user = manager.find(user.class, mail1);              user friend =  manager.find(user.class, mail2);              friend f = new friend();             f.setstatutfriend(statutfriend.tocheck);             friendpk friendpk = new friendpk();             friendpk.setfriend(friend);             friendpk.setuser1(user);             f.setfriendpk(friendpk);              set<friend> relationship = new hashset<friend>();             relationship =  user.getfriends();             relationship.add(f);              set<friend> relationship2 = new hashset<friend>();             relationship2 = friend.getfriends();             relationship2.add(f);              user.setfriends(relationship);             friend.setfriends(relationship2);              manager.persist(user);              t.commit();             error.setreq(statutreq.done);         }         catch(exception e){             error.setreq(statutreq.aborted);             error.seterror(e.getmessage());         }                 {             if (t.isactive())             {                 t.rollback();             }         } 

please indulgent code... i'm beginner ! lot.

at first sight, code seems correct despite architecture looks strange. class friendfk stand ? doesn't user need hold set of users set ? database point of view, relational table necessary not in java model.

if you, delete class , use hbm2dll tool generate correct matching database schema.

could specify hibernate , jars versions , give hibernate config file check it.