The Jave extension was added here in case it ever got deleted from the web.
To use the application under Netbeans, you must first put these files into a Netbeans project and compile it. Then, go in your project folder and select the "dist" folder. Inside you will find the .jar executable file that will launch the application correctly.
Note: When you convert your files there is no loading bar, thus you will have to wait for an unexpected amount of time. A one hour mp4 file takes approximately 2 minutes to be converted.