Android Core

Android Reverse Engineering and Decompilation

Reverse engineering of android java app using apktool, dex2jar, jd-gui to convert .apk file to .java.

By reverse engineering of android app (.apk file) we can get following :

  • understand how a particular UI in an App is constructed
  • reading AndroidManifest.xml – permissions, activities, intents etc in the App
  • native libraries and images used in that App
  • obsfucated code ( android SDK, by default, uses ProGuard tool which shrinks, optimizes, and obfuscates your code by removing unused code and renaming classes, fields, and methods with semantically obscure names.


Required Tools :

Download the followings first.

Using ApkTool

to extract AndroidManifest.xml and everything in res folder(layout xml files, images, htmls used on webview etc..)

Run the following command :

>apktool.bat d sampleApp.apk

It also extracts the .smali file of all .class files, but which is difficult to read.

##You can achieve this by using zip utility like 7-zip.

Using dex2jar

to generate .jar file from .apk file, we need JD-GUI to view the source code from this .jar.

Run the following command :

 >dex2jar sampleApp.apk

Decompiling .jar JD-GUI

it decompiles the .class files (obsfucated- in case of android app, but readable original code is obtained in case of other .jar file). i.e., we get .java back from the application.

Just Run the

jd-gui.exe and File->Open to view java code from .jar or .class file.

You May Also Like –

Reference: Android Reverse Engineering – decompile from our JCG partner Ganesh Tiwari at the GT’s Blog blog.

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10 years ago

With AndroChef Java Decompiler you can decompile apk., dex, jar and java class-files. It’s simple and easy.

Freeman Mobile
Freeman Mobile
9 years ago

This way is just fine!
But JD-GUI homepage has changed!
Follow this tutorial to get updated link of JD-GUI
How to decompile Android APK file

9 years ago


I am very much eager to become a very good Android Development Engineer.I need one help from you.Currently I am having Source files,fully layout file and a manifest file.Will u go through it and compile it and help me.This project will help me out to become a very good Android Engineer.please help me.

Thanks and Regards,

Hey Ganesh
8 years ago

Is is possible to get native libraries using APK file, Thank you!

Manjunatha Reddy
8 years ago

How to retrieve native libraries from apk file.

8 years ago

Is this is possible to read data from a server using modbus protocol. ?

8 years ago

After decompileing the class file to java file in the setContentView the layout name to some 10 digit number how can I find the correct layout with that class. Is there any way to find out.

setContentView (1234567890);

Andrew Rukin
Andrew Rukin
8 years ago

There is new alternative: open-source APK and DEX decompiler called Jadx:
It has online version here:

5 years ago

Really nice post.Thanks for sharing.

5 years ago

I like this post .Thanks for sharing.
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