Adding JDK 6 Javadoc to NetBeans IDE 6

I have been working on this for bl**dy ages...
I google and try a tons of useless tips and trick,
Finally i figure out, it is only some simple steps.
Not complicated at all and no JAR involved.

I would like to share a few useful step here.

Download JDK documentation from
http://java.sun.com/javase/downloads/index.jsp#docs
The site is shutdown temporary.
Try google for mirror site.
Unzip the zip file to the JDK directory
In NetBeans IDE

1. Choose Tools > Java Platform Manager from the main window.
2. Select the platform to which you want to add Javadoc in the left panel of the dialog box.
3. In the Javadoc tab, click Add ZIP/Folder and specify the location of the Javadoc files.
4. Click Close.