Need a portable way to compile. IDE's must use Runtime.exec now to invoke a compiler. This is frowned upon for 100% Pure apps. ISV's are looking for a means where the compiler can be invoked in a user configurable manner (i.e., not dependent on a particular compiler, but perhaps uses javac by default). In addition a means to get results and load compiled code is also necessary.
Note too that the Beans spec encourages the use of adaptors which require code generation. We need a portable way to do this.