Previously, we have seen how to extract contents of .img file and also how to convert dex files to classes/jar . In this post, I'm going to show a method to covert class/classes/jar file to java file(s). To do so, we are going to use a tool, JD-GUI. It is a Java Decompiler, which supports all versions of Java, including java-7. Download the application from here , and extract it to a proper location. Now, open the terminal (in case of Linux) and run the following command: ./jd-gui It will open the GUI window of Java decompiler. Just drag-and-drop a class/jar file into this window. In the left panel, we can find the corresponding java files, arranged in proper package format. To save a single file, select it and choose "Save Source" from the top menu. And to save entire package, choose "Save all sources". Troubleshooting : You may ran into one of these problems, while trying to open jd-gui. Install the packages specified accordingly. Erro...