Project/ServerSession creation error

Question

I have an web-based application that allows users to configure their DB information on a web page.
Upon startup, the application tries to connect to the database with the following code:
Server serverSession = null;
try {
MyProject tlProject = new MyProject(); // My Project is a Project subclass and builds all of the descriptors
DatabaseLogin login = tlProject.getLogin();
serverSession = tlProject.createServerSession(5, 100);
ConnectionPool readPool = new ReadConnectionPool("ReadPool", login, 5, 100, (ServerSession) serverSession);
serverSession.setReadConnectionPool(readPool);
serverSession.initializeIdentityMaps();
serverSession.logMessages();          
serverSession.login();
} catch (DatabaseException de){
if( serverSession != null ){
serverSession.logout();
serverSession.release();
throw de;
If serverSession.login() throws a DatabaseException, the user is redirected to the config page and this operation is repeated until a connection is made.
The problem I am having is that any time at least 1 unsuccessful connection is attempted, I get the following error repeated for every mapped field in the application from TopLink once it connects:
Exception [TOPLINK-48] (OracleAS TopLink - 10g (10.0.3) Developer Preview (Build 030902.1548)): oracle.toplink.exceptions.DescriptorException
Exception Description: Multiple writable mappings exist for the field [T_CUSTOMERS.CUSTOMERID]. Only one may be defined as writable, all others must be specified read-only.
Mapping: com.attask.persist.RKOneToOneMapping[_customer]
Descriptor: RKDescriptor(com.attask.model.RKCustomer--> [DatabaseTable(T_CUSTOMERS)])
It is behaving as if the descriptors are duplicated. I have put debug output everywhere I can, but I can't understand what is happening here. It's as if the descriptor information on the previous connection attempts are being saved somehow and that repetative attempts at logging in to the database cause duplication, but I can't see if this is the case.
Does TopLink cache created ServerSessions/Projects/Descriptors/etc. for unsuccessful DB connection atttempts? Any other ideas what could be causing this error?
If the DB configuraiton information is correct on startup, everything works great. This only happens is unsuccessful attempts are made.

Answer 1

This code snippet is a little abbreviated for this example, but the key steps are all there.
Yes, this code is re-executed until no DatabaseException is thrown. So, the Project creation is done repeatedly, the ServerSession is created repeatedly, etc. When serverSession.login() throws an exception, I clean it up in preparation for another attempt.
I did get this to work by only creating the Project 1 time in a static initializer (basically to make it work like a singleton), and reuse that same instance in repeated attempts. It appears that repeated construction of the Project is causing the duplicate mappings to occur.
MyProject is not a singleton, and it is created programmatically not through the work bench. The constructor for the Project is:
public MyProject(Class[] persistentClasses) {
          setName("myproject");
          setConversionManager();
          buildDescriptors(persistentClasses);
buildDescriptors() iterates through the array of classes and uses static methods defined in the Java classes to programmatically build the descriptor (it was easier to keep the actual class and the mapping info in the same .java file). This sounds like a place where problems could be happening, but the only TopLink interaction in this method is at the very end when it calls:
addDescriptor(descriptor);
The behavior is as if this call to addDescriptor() has a memory outside the Project. If I create a Project and call addDescriptor() where else does this get stored? If other TopLink objects keep a record of this, then this is probably the problem I am seeing.
If this is true, then Project should absolutely be a singleton to prevent this from ever happening.
Nate