I published a process as a Web service. What is the difference between invoking it as a subprocess and invoking it as a Web service?

You can trigger a process from another process in two ways

• Use the Subprocess activity. In this case, you can trigger any process, not just a process that is published as a Web service.
• Use the Web Service activity. In this case, you can only trigger a process that is published as a Web service.

There is an important difference between the above options. If you use the Subprocess activity to trigger another process, the main business process waits for the subprocess to complete all its activities and return the output defined for it before it continues to execute.

However, if you use the Web Service activity to trigger a process, the process is started but does not return any output to the main business process. It only returns the instantiated id to the main process as Web service output.