[Checkers] Need for multiple immutability parameters

[Michael Ernst]

Mahmood-

> > The Checker Framework paper says:
> > 
> >   In just two cases, the programmer would have liked multiple immutability
> >   parameters for an object.  The return value of \<Map.keySet> allows removal
> >   but disallows insertion.  The return value of \<Arrays.asList> is a mutable
> >   list with a fixed size; it allows changing elements but not insertion nor
> >   removal.

When you wrote "changing elements", do you mean "replacing elements"?

If so, then I understand the analogy between the examples.

                     Thanks,

                    -Mike