how to use DEXtoJar

Solution 1:

Follow the below steps to do so_

1. Rename your APK file(e.g., rename your APK file to .zip Ex- test.apk -> test.zip) & extract resultant zip file.
2. Copy your .dex file in to dex2jar folder.
3. Run setclasspath.bat. This should be run because this data is used in the next step.
4. Go to Windows Command prompt, change the folder path to the path of your dex2jar folder and run the command as follows: d2j-dex2jar.bat classes.dex
5. enjoy!! Your jar file will be ready in the same folder with name classes_dex2jar.jar.

Hope this helps you and All reading this... :)

Solution 2:

Step 1 extract the contents of dex2jar.*.*.zip file 
Step 2 copy your .dex file to the extracted directory
Step 3 execute dex2jar.bat <.dex filename> on windows, or ./dex2jar.sh <.dex filename> on linux

Solution 3:

1. Download dex2jar https://code.google.com/p/dex2jar/downloads/list
2. Run dex2jar on apk d2j-dex2jar.sh someApk.apk
3. open jar file in JD GUI http://jd.benow.ca/

Follow this guide: https://code.google.com/p/dex2jar/wiki/UserGuide

--Update 10/11/2016--

Found this ClassyShark from Google's github pretty easy to view code from APK.

https://github.com/google/android-classyshark

// make sure that you downloaded release https://github.com/pxb1988/dex2jar/releases (for the ppl who coldnt find this link in /dex2jar/downloads/list