In Java, I am coding with applet a game where a lizard try to cross the screen avoiding to be died by cars.

I have the following section: init, key released, void start, void paint, void update, void run.

What is the extension of the sound, I need to search?

Then, I want to add that sound in my game. Do I have to add an if statement?

Could you please help me with the code? And where I have to enter it?

Thank you very much.