String userName,userID,classID;
    try {
      Context ctx = new InitialContext();
      UserHome userHome = (UserHome) ctx.lookup("java:/comp/env/User");
      User user = userHome.findByPrimary(Integer.valueOf(userID);
      userHome.remove(userName);
      ClassanduserHome cauHome = (ClassanduserHome) ctx.lookup(
          "java:/comp/env/Classanduser");
      cauHome.create(Integer.valueOf(userID), Integer.valueOf(classID));
    }
    catch (Exception e) {
      sessionContext.setRollbackOnly();
      System.out.println(e.getMessage());
    }
when cauHome.create() throw a Exception
userHome.remove() do not rollback
but when i replace userHome.remove() with user.setName("dfd")
when cauHome.create() throw a Exception
user.setName("dfd") rollback success
who can tell me why?

If the remove() method doesn't rollback, I'd say its not in the same transaction. One way that could happen is if ejbRemove() and setName() don't have the same transactional attributes declared. If that doesn't do it, I'm out of ideas :-)

Mitchell Ratisher :
   can you tell me how to make sure that remove() method and setName() in the
same transaction?

   thanks

Just use the Required transaction attributes for both the EJBs.

i try that but it doesn't work yet