compiling with multiple versions of a class

[Jonathan Gibbons]

Jigsaw folk,

Are there any credible scenarios in which we would expect a single 
compilation to be able to accomodate multiple versions of a class, 
either in a .class or a .java file? If so, are these scenarios 
important, or can we accept as a restriction that any one compilation 
can only handle one version of a class, and that it would be a 
compile-time error for different files in a compilation to depend on 
different versions of a class?

-- Jon