XA interface requires the transaction manager to initialize a resource manager using the
xa_open prior to issuing any other
xa_ calls. JTA requires initialization of a resource manager to be embedded within the resource adapter representing the resource manager. The transaction manager does not need to know how to initialize a resource manager. It must only tell the resource manager when to start and end work associated with a transaction and when to complete the transaction. The resource adapter is responsible for opening (initializing) the resource manager when the connection to the resource manager is established.