Where can I find the source code for the Java library classes? I mean classes in rt.jar.
rt.jar
Platform: Windows.
Sources are in src.zip located in the installation folder:
src.zip
On Windows, the JDK includes src.zip by default if I remember well.
On a Linux distro, you may have to install the sun-java6-source package.
sun-java6-source
On Mac, you'll have to download the Developer Documentation. Have a look at this answer.