If you just got a new android phone, running java applicatons in .jar format can be a real challenge but there are lots of ways out. I previously wrote a post on how to run java applicatons on Android smartphones using an emulator but what I’m posting here is totlally different. Yes, you can convert .jar files to Android’s .apk format. Sounds impossible? Well, it can be done easily with the service of a couple of websites but I need to make a few things clear about Android applications.
Android .apk Files – Can they Really be Decompiled?
You’re probably not an Android developer but just an ordinary guy like me, so I’m going to keep this simple and straight. At first, the extension Google uses for Android applications (.apk) may look complicated but it actually isn’t. Basically, an apk file is nothing but a zip archive disguised in a different extension. You think I’m joking? Just rename the .apk extension to .zip and extract the content to see exactly what I’m trying to say. Inside this zipped archive is a file named classes.dex which is the most important file in there containing all the java files. This file is encrypted but it can still be disassembled. The java classes are compiled differently so there’s need to go through some special steps to decompile them. You’re going to need these two files:
- Dex2Jar from http://code.google.com/p/dex2jar/
- A regular Java decompiler, such as JD from http://java.decompiler.free.fr
-In dex2jar directory, paste your classes.dex file.
-Open CMD, go to dex2jar durectory using cd, and type dex2jar YourApp.apk
-You will automatically get a .jar. Use jd gui to decompile it.
How to Convert .jar/.jad (J2ME/MIDP 2.0) Applications to Android .apk Format
Everything I’ve been ranting about is not the real thing you’re looking, huh? Anyways, I found two sites where you can easily convert .jar applications to .apk format and run it smoothly on your Android smartphone.
This offers this service free of charge and I can tell you that their service is quite cool. You can check them out and, of course, it’s very easy to use. Just upload your java application and the jad format to get the android version! You can use JADMaker to get the .jad version of your java application.
These guys too offer the same service but hey, it’s not for free. If you’re a developer, you may want to check out their service and some extras they’ve got for you.
That’s all I’ve got on converting .jar applications to Android .apk format. There may be other websites offering the same service though.