How to use Netbeans to generate Javadoc

I guess somebody already know this, but I think there are somebody who didn't know it as well, so, I just put it up here.

Next time when you having development in Netbeans, try to write comments using its Auto Comments feature.

So, after all the comments had been write, you just need to right click on the project and click on "Generate Javadoc", then this will come out.