Old farts need to read this paper:
http://www.ecst.csuchico.edu/~julian...than%20C++.pdf

...and understand about runtime optimizations concept:
http://researchweb.watson.ibm.com/pe...eee-survey.pdf

ON increasing type of family of applications JIT-compiled and interpreted programs are as fast or could be even faster than fully precompiled ones.

Android users do not complain the applications would run slowly, even in low end droids.