When toArray is called on the list of Xids in the Txmanager and an array is passed in, it is possible, that the size might not be the same, which will leave nulls in the array being returned.
change....
public Xid[] recover(ConnectionToken dc, int flags) throws Exception

{ Set preparedXids = prepared.keySet(); Xid[] xids = (Xid[]) preparedXids.toArray(new Xid[preparedXids.size()]); return xids; }

to
public Xid[] recover(ConnectionToken dc, int flags) throws Exception

{ Set preparedXids = prepared.keySet(); Xid[] xids = (Xid[]) preparedXids.toArray(); return xids; }

This was related to the patches that we made in the Oswego libraries in JBPAPP-355