This topic contains examples that will help you to better understand how the job user identity (JUID) is assigned in different situations.
In this situation, the Set By value for the JUID is *DEFAULT. Because the job that is running single-threaded, the job user identity is the current user profile under which the initial thread of the job is running (unless, the job user identity was explicitly set by an application). For job queue jobs and completed jobs, the job user identity is the user name from the qualified job name.
In this situation, the Set By value for the JUID is *SYSTEM. Because this is an active job which is currently running as a multi-threaded job, the job user identity is implicitly set by the system. The job user identity is set to the name of the user profile under which the job was running when the job became multi-threaded. When the job returns to running single-threaded, the job user identity will be reset to the *DEFAULT value.
In this situation, the Set By value for the JUID is *APPLICATION. The job user identity is set explicitly by an application using an API. This value applies to both single-threaded and multi-threaded jobs.