With KitKat Google is experimenting on a completely new runtime environment for apps called ART, short for Android Runtime, which is apparently the bee's knees. After a patent spat with Oracle on the Java-based Dalvik runtime that ensnares Android at the moment, Google is obviously determined to create a complete replacement, but that's not the whole story...
Source: http://www.phonearena.com/news/Experimental-Google-ART-runtime-in-Android-KitKat-can-bring-twice-faster-app-executions_id49139
Source: http://www.phonearena.com/news/Experimental-Google-ART-runtime-in-Android-KitKat-can-bring-twice-faster-app-executions_id49139