servlet.jar & j2ee.jar

[Ann Kanu]

What is the difference between servlet.jar and j2ee.jar.
And what is meant by reference implementation (eg Tomcat). Please explain.

[Jeroen Wenting]

servlet.jar contains a subset of the functionality contained in j2ee.jar.
Reference implementation means industry standard. It's meant to be the implementation that's to be used to test whether your application complies with that standard.