There are three classes you can use to invoke IMS DL/I calls:
Collectively, these classes represent the DL/I calls an application program normally makes from IMS. Your program can use these classes to interact with the IMS database (IMS DB), to interact with the IMS transaction manager (IMS TM), and to obtain the system services related to IMS DB and IMS TM. You can also use the IMSSimulationSystem class to test your application on the simulator.