How to find out when all the necessary applet classes are loaded?

I have an applet that sometimes doesn't start up right if you're accessing it for the first time. I was just wondering could the applet start operating even though all the necessary classes wouldn't yet be loaded? And thus failing?
And is there a way to find out when all the classes are loaded, to give the applet the permission to proceed?

The browser and ClassLoader should take care of loading all the classes needed. Are you sure that's your problem? What is the error message(s) you're getting?