[android] Is there a way to get the source code from an APK file?

The hard drive on my laptop just crashed and I lost all the source code for an app that I have been working on for the past two months. All I have is the APK file that is stored in my email from when I sent it to a friend.

Is there any way to extract my source code from this APK file?

I developed a Tool - Code Analyzer, it runs in iPhone/iPad/Mac, to analyze Java/Android files, https://decompile.io

While you may be able to decompile your APK file, you will likely hit one big issue:

it's not going to return the code you wrote. It is instead going to return whatever the compiler inlined, with variables given random names, as well as functions given random names. It could take significantly more time to try to decompile and restore it into the code you had, than it will be to start over.

Sadly, things like this have killed many projects.
For the future, I highly recommend learning a Version Control System, like CVS, SVN and git etc.

and how to back it up.

Below ONLINE tool:

http://www.javadecompilers.com/apk

it do ALL by one click: decompiled .java files + resources + xml (in one .zip file) with very good decompiler (jadx return java code in places/functions where other compiles return comments inside function like "unable to decompile" or some android assembler/machine code)

Use this tool http://www.javadecompilers.com/

But recently, a new wave of decompilers has forayed onto the market: Procyon, CFR, JD, Fernflower, Krakatau, Candle.

Here's a list of decompilers presented on this site:

CFR - Free, no source-code available, http://www.benf.org/other/cfr/ Author: Lee Benfield

Very well-updated decompiler! CFR is able to decompile modern Java features - Java 9 modules, Java 8 lambdas, Java 7 String switches etc. It'll even make a decent go of turning class files from other JVM langauges back into java!

JD - free for non-commercial use only, http://jd.benow.ca/ Author: Emmanuel Dupuy

Updated in 2015. Has its own visual interface and plugins to Eclipse and IntelliJ . Written in C++, so very fast. Supports Java 5.

Procyon - open-source, https://bitbucket.org/mstrobel/procyon/wiki/Java%20Decompiler Author: Mike Strobel

Fernflower - open-source, https://github.com/fesh0r/fernflower Author: Egor Ushakov

Updated in 2015. Very promising analytical Java decompiler, now becomes an integral part of IntelliJ 14. (https://github.com/JetBrains/intellij-community/tree/master/plugins/java-decompiler) Supports Java up to version 6 (Annotations, generics, enums)

JAD - given here only for historical reason. Free, no source-code available, jad download mirror Author: Pavel Kouznetsov

apktool will work. You don't even need to know the keystore to extract the source code (which is a bit scary). The main downside is that the source is presented in Smali format instead of Java. Other files such as the icon and main.xml come through perfectly fine though and it may be worth your time to at least recover those. Ultimately, you will most likely need to re-write your Java code from scratch.

You can find apktool here. Simply just download apktool and the appropriate helper (for Windows, Linux, or Mac OS). I recommend using a tool such as 7-zip to unpack them.

There's an app for that and generally takes just a few clicks and you are done. https://github.com/Nuvolect/DeepDive-Android

1. Select Apps, under "Installed Apps" select your app. If it is not there you can load the APK.
2. Select "Extract APK"
3. Select "Unpack APK"
4. Select "Decompile with Jadx". This can take a few seconds or a few minutes depending on the speed of your device

After that you can browse the source code, download it to another computer with elFinder or search through it using Lucene.

In addition to Jadx it has CFR and Fernflower decompilers.

This site https://www.apkdecompilers.com/ did it automatically.

I tried the site mentioned in the accepted answer first but that didn't work for me.

I personally recommend Show Java Android App to get the source code. You can download it from play store or from here

Step 1: Make a new folder and copy over the .apk file that you want to decode.

Now rename the extension of this .apk file to .zip (e.g. rename from filename.apk to filename.zip) and save it. Now you can access the classes.dex files, etc. At this stage you are able to see drawables but not xml and java files, so continue.

Step 2: Now extract this .zip file in the same folder (or NEW FOLDER).

Download https://github.com/pxb1988/dex2jar/releases/tag/2.0 : dex2jar-2.0

Now open command prompt and change directory to that folder (or NEW FOLDER). Then execute : d2j-dex2jar.bat classes.dex

Download this decompiler http://java-decompiler.github.io/ to decompile classes-dex2jar.jar

Step 3: Now open another new folder

Put in the .apk file which you want to decode

Download the latest version of apktool AND apktool (https://ibotpeaches.github.io/Apktool/install/) install window (both can be downloaded from the same link) and place them in the same folder

Open a command window

Now run command like apktool if framework-res.apk (if you don't have it get it here)and next

apktool d myApp.apk (where myApp.apk denotes the filename that you want to decode)

now you get a file folder in that folder and can easily read the apk's xml files.

Copycontents of both folders to a single folder

Done !

I found the following as the simplest method:

1. Rename your app.apk to app.zip (Change extension from apk to zip)
2. Extract the zip file into a folder
3. Use JADX tool to read the source code, present in classes.dex file.

The simplest way is using Apk OneClick Decompiler. That is a tool package to decompile & disassemble APKs (android packages).

FEATURES

• All features are integrated into the right-click menu of Windows.
• Decompile APK classes to Java source codes.
• Disassemble APK to smali code and decode its resources.
• Install APK to phone by right-click.
• Recompile APK after editing smali code and/or resources. During recompile:
• Optimize png images
• Sign apks
• Zipalign

REQUIREMENTS

Java Runtime Environment (JRE) must be installed.

You can download it from this link Apk OneClick Decompiler

Enjoy that.

This is an alternative description - just in case someone got stuck with the description above. Follow the steps:

1. download apktool.bat (or apktool for Linux) and apktool_<version>.jar from http://ibotpeaches.github.io/Apktool/install/
2. rename the jar file from above to apktool.jar and put both files in the same folder

3. open a dos box (cmd.exe) and change into that folder; verify that a Java Environment is installed (for Linux check the notes regarding required libraries as well)
4. Start: apktool decode [apk file]

   Intermediate result: resource files, AndroidManifest.xml

5. unzip APK file with an unpacker of your choice

   Intermediate result: classes.dex

6. download and extract dex2jar-0.0.9.15.zip from http://code.google.com/p/dex2jar/downloads/detail?name=dex2jar-0.0.9.15.zip&can=2&q=
7. drag and drop classes.dex onto dex2jar.bat (or enter <path_to>\dex2jar.bat classes.dex in a DOS box; for Linux use dex2jar.sh)

   Intermediate result: classes_dex2jar.jar

8. unpack classes_dex2jar.jar (might be optional depending on used decompiler)
9. decompile your class files (e.g. with JD-GUI or DJ Decompiler)

   Result: source code

Note: it is not allowed to decompile third party packages; this guide is intended to recover personal source code from an APK file only; finally, the resulting code will most likely be obfuscated

I've been driving myself crazy for days trying to get dex2jar to work on a fedora 31 laptop against an apk that just wasn't going to work. This python 3 script did the trick in minutes and installing jd-gui made class files human readable.

http://java-decompiler.github.io/

https://github.com/Storyyeller/enjarify

specifically, here's what I ran:

# i installed apktool before the rest of the stuff, may not need it but here it is
$> cd /opt
$> sudo mkdir apktool
$> cd apktool/
$> sudo wget https://raw.githubusercontent.com/iBotPeaches/Apktool/master/scripts/linux/apktool
$> sudo wget https://bitbucket.org/iBotPeaches/apktool/downloads/apktool_2.4.1.jar
$> sudo mv apktool_2.4.1.jar apktool.jar
$> sudo mv apktool* /usr/bin/
$> sudo chmod a+x /usr/bin/apktool*

# and enjarify
$> cd /opt
$> sudo git clone https://github.com/Storyyeller/enjarify.git
$> cd enjarify/
$> sudo ln -s /opt/enjarify/enjarify.sh /usr/bin/enjarify

# and finally jd-gui
$> cd /opt
$> sudo git clone https://github.com/java-decompiler/jd-gui.git
$> cd jd-gui/
$> sudo ./gradlew build

# I made an alias to kick of the jd-gui with short commandline rather than long java -jar blahblahblah :)
$> echo "jd-gui='java -jar /opt/jd-gui/build/launch4j/lib/jd-gui-1.6.6.jar'" >> ~/.bashrc

Now one should be able to rum the following to get class files:

$> enjarify yourapkfile.apk

And to start jd-gui:

$> jd-gui

Then just open your class files!

apktool is the best thing you can try. I have saved some xml with it, but honestly I don't know how it will work with the .java code.

I would recommend you to have a code repository even if your are the only coder. I've been using Project Locker for my own projects. It gives you free svn and git repos.

1. Extracting the source from a native Android application

The source code of a native Android application is not difficult to obtain, but it does require extra tools that are compatible with Windows, Mac, and Linux. My personal favorites when it comes to tools are dex2jar and JD-GUI.

If you’re unfamiliar with these tools, dex2jar will read Dalvik Executable files and convert them to the standard JAR format. JD-GUI will read JAR files and decompile the class files found in them.

To make the extraction process easier to understand, let’s start by creating a fresh native Android project:

android create project --target 19 --name TestProject --path . --activity TestProjectActivity --package com.nraboy.testproject

The above command will leave you with an Android project in your current command prompt path.

Since our project has an Activity class already included, lets jump straight into the build process. You can give me a hard time all day long about using Ant instead of Gradle or Maven, but for this tutorial I’m going to stick with it.

ant debug

The above command will create a debug build typically found at bin/TestProject-debug.apk.

Using your favorite unzip tool, extract the APK file. 7-zip is a popular tool, but if you’re on a Mac you can just run the following from the Terminal:

unzip TestProject-debug.apk

This will leave us with a bunch of files and folders, but one is important to us. Make note of classes.dex because it contains all of our source code. To convert it into something readable we need to run dex2jar on it. You can use dex2jar on Mac, Linux, and Windows, but I’m going to explain from a Mac perspective.

With the classes.dex file in your extracted dex2jar directory, run the following from the Terminal:

./dex2jar.sh classes.dex

Open the JD-GUI application that you downloaded because it is now time to decode the JAR and packaged class files. Open the freshly created classes_dex2jar.jar file and you should see something like the following:

See how easy it was to get to the source code of your native Android APK? Now what can you do to better protect yourself?

The Android SDK ships with Proguard, which is a obfuscation module. What is obfuscation you ask?

Obfuscation via Wikipedia:

Obfuscation (or beclouding) is the hiding of intended meaning in communication, making communication confusing, willfully ambiguous, and harder to interpret.

While obfuscation will not encrypt your source code, it will make it more difficult to make sense of. With Proguard configured, run Ant in release mode and your code should be obfuscated on build.

2. Extracting the source from a hybrid Android application

The source code of hybrid applications are by far the easiest to extract. You don’t need any extra software installed on your computer, just access to the APK file.

To make things easier to understand, lets first create a fresh Apache Cordova project and then extract it. Start by doing the following:

cordova create TestProject com.example.testproject TestProject
cd TestProject
cordova platform add android

During the project creation process you are left with the default Apache Cordova CSS, HTML, and JavaScript templates. That is fine for us in this example. Let’s go ahead and build our project into a distributed APK file:

cordova build android

You’re going to be left with platforms/android/ant-build/CordovaApp-debug.apk or something along the lines of platforms/android/ant-build/*-debug.apk.

Even though this is a debug build, it is still very usable. With 7-zip or similar installed, right click the APK file and choose to extract or unzip it. In the extracted directory, you should now have access to all your web based source files. I say web based because any Java files used by Apache Cordova will have been compiled into class files. However, CSS, HTML, and JavaScript files do not get touched.

You just saw how depressingly easy it is to get hybrid application source code. So what can you do to better protect yourself?

You can uglify your code, which is a form of obfuscation.

Doing this will not encrypt your code, but it will make it that much more difficult to make sense of.

If you want to uglify your code, I recommend you install UglifyJS since it is pretty much the standard as of now. If you prefer to use a task runner, Grunt and Gulp have modules for UglifyJS as well.

May be the easy one to see the source:

In Android studio 2.3, Build -> Analyze APK -> Select the apk that you want to decompile.
You will see it's source code.

Link for reference:
https://medium.com/google-developers/making-the-most-of-the-apk-analyzer-c066cb871ea2

based on your condition, if your android apk:

Condition1: NOT harden (by Tencent Legu/Qihoo 360/...)

Choice1: using online service

such as:

using www.javadecompilers.com

goto:

• http://www.javadecompilers.com/apk
  • Note: internally using Jadx

to auto decode from apk to java sourcecode

steps:

upload apk file + click Run + wait some time + click Download to get zip + unzip ->

sources/com/{yourCompanyName}/{yourProjectName}

is your expected java source code

Choice2: decompile/crack by yourself

use related tool to decompile/crack by yourself:

use jadx/jadx-gui convert apk to java sourcecode

download jadx-0.9.0.zip then unzip to got bin/jadx, then:

• command line mode:
  • in terminal run: jadx-0.9.0/bin/jadx -o output_folder /path_to_your_apk/your_apk_file.apk
  • output_folder will show decoded sources and resources
    • sources/com/{yourCompanyName}/{yourProjectName} is your expected java sourcecode
• GUI mode
  • double click to run jadx-0.9.0/bin/jadx-gui (Linux's jadx-gui.sh / Windows's jadx-gui.bat)
  • open apk file
  • it will auto decoding -> see your expected java sourcecode
  • save all or save as Gradle project

eg:

Condition2: harden (by Tencent Legu/Qihoo 360/...)

the main method of 3 steps:

1. apk/app to dex
2. dex to jar
3. jar to java src

detailed explanation:

Step1: apk/app to dex

use tool (FDex2/DumpDex) dump/hook out (one or multiple) dex file from running app

steps:

prepare environment

• a rooted android
  • real phone
  • or emulator
    • here using Chinese Nox App Player???????
      • 
• install your android apk
  • to the phone or emulator
• installed Xposed Installer
  • 
• install FDex2/DumpDex into XPosed and enable it
  • 
  • Note: need restart Xposed to make FDex2 work
  • FDex2 download address, Chinese:
    • ???? FDex2-CSDN??
    • ??: https://pan.baidu.com/s/1lTF8CN96bxWpFwv7J174lg ???: 3e3t
• install your android apk to phone/emulator

dump out dex from running app

• run FDex2 then click your apk name to enable later to capture/hook out dex

  • 
• (in phone/emulator) run your app
• find and copy out the dump out whole apk resources in /data/data/com/yourCompanyName/yourProjectName
  • in its root folder normally will find several dex file
  • 

Step2: dex to jar

use tool (dex2jar) convert (the specific, containing app logic) dex file to jar file

download dex2jar got dex-tools-2.1-SNAPSHOT.zip, unzip got dex-tools-2.1-SNAPSHOT/d2j-dex2jar.sh, then

sh dex-tools-2.1-SNAPSHOT/d2j-dex2jar.sh -f your_dex_name.dex

eg:

dex-tools-2.1-SNAPSHOT/d2j-dex2jar.sh -f com.xxx.yyy8825612.dex
dex2jar com.xxx.yyy8825612.dex -> ./com.xxx.yyy8825612-dex2jar.jar

Step3: jar to java src

use one of tools:

• Jadx
• Procyon
  • GUI tool based on procyon:
    • Luyten
    • Bytecode Viewer
• CRF
• JD-GUI
• some others:
  • Krakatau
  • Fernflower
  • Cavaj

convert jar to java src

for from jar to java src converting effect:

Jadx > Procyon > CRF >> JD-GUI

so recommend use: Jadx/jadx-gui

steps:

• double click to run jadx-gui
• open dex file
• File -> save all

eg:

exported java src:

More detailed explanation can see my online ebook Chinese tutorial:

• ??????????
  • tutorial's source code on github: crifan/android_app_security_crack: ??????????

There are a few ways to do this:

1. Use the "Profile or Debug APK" feature in Android Studio 3.0.

   It allows you to open and explore APKs in Android Studio. Classes are decompiled into smali. Resources are not extracted and things like "Go to Definition", "Find All References" and debugging don't work without the source code (android studio 3.0 canary 9). Some additional smali features might work with smalidea.

   

   

   

2. Use jadx.

   Jadx decompiles the code in a given APK to java source files.

   

3. Use apktool.

   Apktool is a command line tool which extracts resources and decompiles code into smali for a given apk. You can recompile using apktool also. Here's an example of it in action:

   $ apktool d test.apk
   I: Using Apktool 2.2.4 on test.apk
   I: Loading resource table...
   I: Decoding AndroidManifest.xml with resources...
   I: Loading resource table from file: 1.apk
   I: Regular manifest package...
   I: Decoding file-resources...
   I: Decoding values */* XMLs...
   I: Baksmaling classes.dex...
   I: Copying assets and libs...
   I: Copying unknown files...
   I: Copying original files...
   $ apktool b test
   I: Using Apktool 2.2.4 on test
   I: Checking whether sources has changed...
   I: Smaling smali folder into classes.dex...
   I: Checking whether resources has changed...
   I: Building resources...
   I: Building apk file...
   I: Copying unknown files/dir...
   

apktool is THE way to go. Online apktool service exists as well: http://www.javadecompilers.com/apktool

Some limitations, obviously, exist due to the service ‘online nature’: you may extract and research assets and the manifest file, but it is impossible to recompile the application at the moment.

Still, this is a no-hassle way to 'open' the android application.

I'll show you other way to decompile the .apk files.

You can follow the first 2 steps from "prankul garg". So you have another opportunities:

Step 3':

Download the "JD-GUI", thats easy to found this one. Open your .jar file in "jd-gui.exe". (File > Open file > 'found your .jar file'). After this procedure, you can save all resources in a .zip file.

So,

1st - You have to rename the .apk file to .zip

2nd - You have to decode .dex file (if you want, decode the .apk file to dex2jar, that's possible)

3rd - You have to decode .jar file with JD-GUI

There are lots of applications and methods in the market to decompile the apk file into java class but if the app is compiled with ProGuard rule then you are in a big trouble because this rule will shrink all the dex files into a small character name and then you can not trace back the implementation. see https://developer.android.com/studio/build/shrink-code for mode clarification.

Happy Coding...

You can try DexPatcher. It even integrates with Android Studio. It uses Apktool and Dex2Jar internally.
You can use those tools independently as well. Apktool decompiles apk, and extracts .dex files, which can further be converted to jar using Dex2Jar. Jar can be decompiled by using JD-GUI. You can see the Java code with the help of that tool. Although the similarity of decompiled code to the actual code cannot be guaranteed. There are some advanced code obfuscation tools available in the market, which mess up the code to make it difficult to decompile / understand. eg. Proguard

Yes, it is possible.

There are tons of software available to reverse engineer an android .apk file.

Recently, I had compiled an ultimate list of 47 best APK decompilers on my website. I arranged them into 4 different sections.

1. Open Source APK Decompilers
2. Online APK Decompilers
3. APK Decompiler for Windows, Mac or Linux
4. APK Decompiler Apps

I hope this collection will be helpful to you.

Link: https://www.edopedia.com/blog/best-apk-decompilers/

There is also a new application on the Play Store with which it is possible to decompile an apk (system applications too) and view the source code right on your smartphone. It saves the files to your SD card so you can view it on your computer too. It does not require root or something else.

Just install and have fun. I think this is the easiest way to decompile an app.

Android studio offers you to analyse any apk file.

1 - From build menu choose analyse apk option and select apk file. 2 - This will result in you the classes.dex file and other files. 3 - Click on classes.dex which will give you the list of folders, packages, libraries and files. 4 - From and android studio settings install a plugin called "Dex to Jar" 5 - click on any activity file of your extracted project and choose dex to jar from the build menu.

This will result in you the actual code of your java file.

Cheers.

These two articles describe how to combine the use of apktool and dex2jar to take an APK file and create an Eclipse project that can build and run it.

http://blog.inyourbits.com/2012/11/extending-existing-android-applications.html

http://blog.inyourbits.com/2012/12/extending-existing-android-applications.html

Basically you:

1. Use apktool to get the resource files out of the apk
2. Use dex2jar to get a jar file that contains the classes in a format that Eclipse will like.
3. Create an Eclipse project point it at the resource files and the new jar file
4. Open the jar file with a zip utility and delete the existing resources
5. Open the jar file with JDGui to view the source code
6. Take whatever source code you need from JDGui, stick it in a class inside Eclipse and modify it
7. Delete that class from the jar file (so you don't have the same class defined multiple times)
8. Run it.

Apktool for reverse engineering 3rd party, closed, binary Android apps.

It can decode resources to nearly original form and rebuild them after making some modifications.

It makes possible to debug smali code step by step. Also it makes working with an app easier because of project-like file structure and automation of some repetitive tasks like building apk, etc.

http://ibotpeaches.github.io/Apktool/