Foursquare Place Picker SDK
· A simple library to allow your users to pick a location or for the developer to grab the current location of the device mapped to a Foursquare venue
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 placepicker-0.7.0.jar file.
Once you open a JAR file, all the java classes in the JAR file will be displayed.