When going over the low level QueryableStateClient with Nico Kruber we noticed that the key hashCode argument can be confusing to users:
The keyHashCode argument is the result of calling hashCode() on the key to look up. This is what is send to the JobManager in order to look up the location of the key. While pretty straight forward, it is repetitive and possibly confusing.
As an alternative we suggest to make the method generic and simply call hashCode on the object ourselves. This way the user just provides the key object.
Since there are some early users of the queryable state API already, we would suggest to rename the method in order to provoke a compilation error after upgrading to the actually released 1.2 version.
(This would also work without renaming since the hashCode of Integer (what users currently provide) is the same number, but it would be confusing why it acutally works.)