Apktool – This tool is used for reverse engineering third party, closed, binary Android applications.
Dex2jar – This widely available tool works with Android .dex and Java .class files, enabling the conversion of one binary format to another.
JD-GUI – This is a graphic utility tool that stands alone and displays Java sources from .class files.
In addition to manual coding, there are many applications built around hacking Android systems. These range from apps targeted at end users who want to extend their Android device's battery life or customize other parts of its operating system to deep system hacks used by more sophisticated hackers and attackers.
