Data source login + ServerSession + uow

Question

Can anyone please provide assistance as to what lines of code is necessary to be able to create a ServerSession, then login using the username and password of the data sources of OC4J, and then acquire a unit of work to be used in doing read and write transactions against a 9i database. My toplink version is 10g (9.0.4). The following are snippets of my java code:
ServerSession session = null;
session = (ServerSession)SessionManager.getManager().getSession("session");
// I didn't put session.login() because I
// read somewhere that there is already an implicit
// login when the ServerSession (session variable) was
// created via the second line above.
UnitOfWork unitOfWork;
System.out.println("step3.1");
Session session1 = (Session) session.acquireClientSession();
unitOfWork = session1.acquireUnitOfWork();
// the problem is, at this point of acquiring a unit of
// work, at runtime, I already encounter a
// java.lang.NullPointerException. Does it mean that my
// assumption of an implicit login during the
// ServerSession creation is not correct?
Please help. I guess this are still the basic stuff of Toplink but the standard Toplink documentations don't seem to help. Thanks in advance.

Answer 1

For the benefit of others, my unit of work is now defined as:
unitOfWork = getServerSession().acquireClientSession().acquireUnitOfWork();
Likewise, I have included in my session bean the following methods:
public void login() {
// Get a Server Session from the sessions xml
ServerSession aSession = (ServerSession)SessionManager.getManager().getSession("Session");
aSession.login();
setServerSession(aSession);
public static void logout() {
if (getServerSession() != null) {
getServerSession().logout();
protected static ServerSession serverSession = null;
private static ServerSession getServerSession() {
return serverSession;
private void setServerSession(ServerSession session) {
this.serverSession = session;
With this, all i have to do is invoke login() to establish a database login.
Anthony
Philippines