Open source Application demonstrating layer Architcture

Question

Many of u will agree that learning from open source project is another way of improving programming skills .Can me make list of open source applications that best demonstrates the use of layer architecture.

Answer 1

I'm not sure it fits exactly your needs, but the source code of Ignite Realtime's Openfire Server is really nicely organized. It was a pleasure to modify its source to the needs of a company I worked for a few years ago.

Answer 2

It depends on what kind of application you would like to see. I find Kigg a good example of layered architecture, if we talk about a web application. It is written in asp.net mvc and has a nice separation of concerns\responsibilities.