Adjust polling since spec doesn't guarantee you can poll on a single JobExecution.

It is valid per the specification for a **JobExecution** object to contain a snapshot of status and other data.  It is not required to contain a "live" view into the repository.    I know the WebSphere Liberty Profile (beta) batch support uses the snapshot approach, and presumably Spring Batch does at well since they raised the issue against the TCK at one point when it was assuming "live" data.

Updated with an equivalent solution that should work with either approach.