Making Harmony modular enouth to be kind of a JVM framework cannot be done before having a working JVM. There is a lot of literature about how frameworks should emerge from continuous design and development.
There's a lot of literature about all aspects of development that has been gleefully ignored at the ASF :-)
This must not be the focus until required, so no JIT plugable layer until someone tries to write another JIT for Harmony (emphasis on another).
Creating such is a big chalenge, to guess what spots need to flexible and the others that don't. Guess what, people often make bad guesses about these and in the end we have a very complex design with a lot of shortcomings.
There's a difference between having a framework and making the detailed decisions about where flexibility is required.
IMO, a good framework lets you change your mind about where the hooks are with ease. The system we use for hooks in httpd 2.0 is an example (ok, I'm biased, I wrote it).
http://httpd.apache.org/docs-2.0/developer/hooks.html
explains hooks, but there's also another related facility - optional functions - these are functions provided by modules that may or may not be present. They're rather like hooks, except there's only one of them (if you see what I mean). There is doxygen documentation but it seems not to be online :-(
BTW, what that documentation doesn't make clear is that hook code is type-safe throughout (except in the core implementation of the hook handling code itself, of course).
Cheers,
Ben.
-- http://www.apache-ssl.org/ben.html http://www.thebunker.net/
"There is no limit to what a man can do or how far he can go if he doesn't mind who gets the credit." - Robert Woodruff
