Make getMethodID/findClass pure

[alpmestan]

When one of these two functions is called with a literal method name, the compiler can automatically float the call to top level and make it a CAF, thus seamlessly sharing method lookups across all callers.

Methods are static objects: they don't change over time. Unless of course you take into account class unloading. But that's like saying all calls to any function in any dynamic library should be in IO, because the library could be unlinked from the address space conceivably.

Alternatively, the user could memoize calls manually, by maintaining and passing around hash tables. This is obviously less than ideal.

[mboes]

This issue was moved to tweag/inline-java#5