If you are referring to the process ID, it is not exposed in the API.
Process management is hung together through many tables. If you go looking at the tables in the 'adobe' schema you can piece together the relationship between invocation ids, task ids, process ids, etc.
In the case of the jobId that is defined in the ActionScript API, the equivalent value will surface in numerous tables, including the column long_lived_invocation_id in the table adobe.tb_process_instance and the column public_id in the table adobe.tb_job_instance.
So if you really had to you could use the JDBC Service and build a query to find what you are looking for.