Not in the Android performance picture so far: language runtimes (e.g., jruby and groovy) that dynamically generate bytecode. A JIT can optimize it (and for jruby and grovvy on the jvm, it typically does).

That hasn't been an issue on Android so far because those language runtimes would have had to be retooled to generate Dalvik bytecode, and none of them were. (Ruboto, jruby on Android, runs in pure interpreted mode, with a significant performance hit.) But I believe that with Dalvik, it was technically possible. Does ART just close this possibility off?