Here's your start() method (I'm guessing this is an
applet If runThread is null when this method is called, you'll get a NullPointerException when it tries to call start() on a null variable. Otherwise, if runThread is non-null, then it won't call start(), in turn, on it! Therefore, you don't see "RUN!" because the Thread is never started.
I think the simplest change that will fix the immediate problem is to change this "==" to a "!=".
There are all sorts of other problems with what you've shown here; the most important is that the deprecated stop() method should almost
never be used, and in fact suspend() and resume() should be approached with great caution -- but we'll cross that bridge when we come to it.