Many people ask if they can save the morse code sounds to audio files on their computers.
The problem is the security restrictions placed on Java applets. Java applets come from a web server but they run on your computer. The designers of Java and the web browser applet mechanism tried to make it possible to run signed, trusted, applets that would be allowed to escape the sandbox to do useful things like save a file. But they didn't do a very good job. There are four different schemes for building a signed applet, and none of them work on most Java-enabled browsers.