FilePicker
· All file and media picker library for android. This library is designed to simplify the process of selecting and retrieving media files from an Android device, and supports media capture for images and videos.
Download JD-GUI to open JAR file and explore Java source code file (.class .java)
Click menu "File → Open File..." or just drag-and-drop the JAR file in the JD-GUI window FilePicker-0.1.9.jar file.
Once you open a JAR file, all the java classes in the JAR file will be displayed.