JDO Question

[Patrick Cheung]

hi all,
may i ask a question about jdo?
i am using triactive jdo to do a project. i wrote a program to query the database with some condition. but when i commit the transaction, i can no longer read the properties in the object. as below.
Extent ext = pm.getExtent(User.class, true);
String filter = "account==acc";
Query q = pm.newQuery(ext, filter);
String parameter = "java.lang.String acc";
q.declareParameters(parameter);
tx.begin();
Collection c = (Collection)q.execute("admin");
ArrayList list=new ArrayList(c);
System.out.println(list.size()); //returns the amount of result
System.out.println(user); //returns user informations
tx.commit();
System.out.println(user); //returns null
can anybody tell me how to keep the informations available after "tx.commit()"?
thanks in advance.
Patrick