If an application running as a service uses databases and files but does not contain any transactional logic, it can let the application container manage its resources.
The application container must know in advance what resource managers will be required. You define resources not by service, but by enterprise server instance. You can only define resource managers that are XA-compliant.
When an enterprise server instance and its service execution processes start up, the enterprise server manager opens connections to all the resources that might be needed by the services that run in that enterprise server instance. When a container-managed service is invoked, the enterprise server manager performs all file and database actions that it requires.
The application container manages databases by issuing XA commands.
The application container decides whether to commit or roll back resources using information supplied when the enterprise server instance was created and deployed in your COBOL development system. However, if there is an error in the application container itself, resources are always rolled back.