Where to see Java source code?

One fine day while I was programming, I wanted to see the source code for java.lang.Math class. I sSearched online but could not find any easy way. Later found that the code is already on my machine (since I had the JDK).

The source code is located in the JDK installation directory with name src.zip!
(Other option was www.docjar.com)

Next post, how the java source code helped me!