Open a container, with the transaction's default locking policy.
Note that if NOWAIT has been specified lock will be requested with no wait time, and if lock is not granted a SQLState.LOCK_TIMEOUT exception will be thrown.
The release() method of ContainerHandle will be called when this transaction is aborted or commited, it may be called explicitly to release the ContainerHandle before the end of the transaction.
@return a valid ContainerHandle or null if the container does not exist.
@exception StandardException Standard Derby exception policy