The Android OS that powers most of the world’s smartphones has gone through quite a few changes since its launch in 2008 creating a completely new interactive ecosystem for multimedia and apps.

With the release of the new Android Lollipop, Google will also replace the existing app development tools, ‘javac’ and ‘dex’ with two new build tools called ‘Jack’ and ‘Jill’ (like the nursery rhyme).

The current development tools ‘Javac’ and ‘dex’ operate with a 2-step process that begins with javac converting source code into standard Java bytecode, then the dex compiler is responsible for turning that into Dalvik bytecode so it can run on Android. With Jack and Jill, the process is similar, but with a few important distinctions.

To begin with, there’s Jack’s compiler (compilers convert the source code into an executable programming language), it converts the Java source code directly to .dex format, removing Java bytecode from the process. The Jill compiler then adds a new preprocessing and caching step. It shields Jack from Java bytecode by converting it to intermediate Jayce bytecode, Jack then converts the java source code and the intermediate Jayce bytecode to dalvik byte code.

With the old Javac, Android developers were reliant on implementations controlled by the likes of Oracle or Eclipse. With a brand new compiler, Google can add features, improve development processes and directly manage the outcome without worrying how these changes will affect the larger ecosystem built around Java.

What this ultimately means is the time spent for converting the source code into an executable programming language (java source code to dalvik byte code) is considerably faster, saving developers a lot of time.