Expose the internal map in ExecutionContext as read-only #4004
Description
The current code is exposing this.map.entrySet() instead of this.map.
JobContext and StepContext are converting to Map using EntrySet.
Also, the entrySet is being exposed as modifiable.
I think, If the map being exposed is read-only, there is no problem.
This does not violate this comment. (It is a thin wrapper for a map that allows optionally for type safety on reads.)
I want to add a method that exposes the inner map. if so no longer need to create maps unnecessarily.