Client support for transactions
This topic describes the support of application clients for the use of transactions.
Application clients running in a J2EE client container can explicitly demarcate transaction boundaries as described in Using component-managed transactions. Application clients cannot perform, directly within the client container, transactional work in the context of any global transaction that they start, because the client container is not a recoverable process.
Application clients can make requests to remote objects, such as enterprise beans, within the context of a client-initiated transaction. Any transactional work performed in a remote, recoverable server process is coordinated as part of the client-initiated transaction. The transaction coordinator is created on the first server process to which the client-initiated transaction is propagated.
A client can begin a transaction then, for example, access a JDBC data source directly in the client process. In such cases, any work performed through the JDBC provider is not coordinated as part of the global transaction. Instead, the work runs under a resource manager local transaction. The client container process is non-recoverable and contains no transaction coordinator with which a resource manager can be enlisted.
A client can begin a transaction then call a remote application component, such as an enterprise bean. In such cases, the client-initiated transaction context is implicitly propagated to the remote application server where a transaction coordinator is created. Any resource managers accessed on the recoverable application server (or any other application server hosting application components invoked by the client) are enlisted in the global transaction.
Client application components need to be aware that locally-accessed resource managers are not coordinated by client-initiated transactions. Client applications acknowledge this through a deployment option that enables access to the UserTransaction interface in the client container. By default, access to the UserTransaction interface in the client container is not enabled. To enable UserTransaction demarcation for an application client component, set the Allow JTA Demarcation extension property in the client deployment descriptor. For information about editing the client deployment descriptor, see Editing deployment descriptors.