If the tx is not active (for example it has STATUS_PREPARING), then the method always returns null, even if the associated CloseConnectionSynchronization exists.
This results in wrong warnings about non-closed connections, since when the close() is called for a connector, in CachedConnectionManager.unregisterConnection() a null value is returned from getCloseConnectionSynchronization() and the connector remains in the list of non-closed resources for the transaction.
I think this bug was introduced here: http://jira.jboss.com/jira/browse/JBAS-31#action_12310798
I propose the following solution:

— CachedConnectionManager.java.orig 2005-11-22 02:10:41.000000000 +0200
+++ CachedConnectionManager.java 2007-09-04 18:42:48.000000000 +0300
@@ -544,13 +544,13 @@
try
{
Transaction tx = tm.getTransaction();

• if (TxUtils.isActive(tx))
  + if (tx != null)
  {
  TransactionSynchronizer.lock(tx);
  try
  {
  CloseConnectionSynchronization cas = (CloseConnectionSynchronization) TransactionSynchronizer.getCCMSynchronization(tx);
• if (cas == null && createIfNotFound)
  + if (cas == null && createIfNotFound && TxUtils.isActive(tx))
  {
  cas = new CloseConnectionSynchronization();
  TransactionSynchronizer.registerCCMSynchronization(tx, cas);