will a job do an implicit COMMIT?

I have a job that calls a stored procedure, specified like this:

   job_type        => 'PLSQL_BLOCK',
   job_action      => 'begin qrunner_util.purge; end;',

Will the job system perform a COMMIT after it performs the action? Or should I add the commit to the action:

   job_action => 'begin qrunner_util.purge; commit; end;',

Many TIA!
Mark

-- 
Mark Harrison
Pixar Animation Studios