Here are some architecture diagrams for Spring Framework 2.1 M3 (released yesterday). You can point the (free) structure101 plug-in at these and get IDE warnings if your customizations break Jeurgen’s architecture.
Here is the top level breakout of org.springframework:
Structure101 created this from the physical code-base. All the cells in the diagram use only lower-level cells. With such a clean structure, I did no further editing of the diagram, other than to adjust the level of nesting.
Below is a further breakout of some of the larger modules.
You can view these online here (I’ll update later today), and if you have a Spring-based project, you could install the structure101 Eclipse or IntelliJ plug-in (free from here) and point it to the Spring project in the online repository (use this url: http://www.structure101.com/java/data in the plug-in properties) and the diagrams will be visible inside your IDE, any existing violations flagged (i.e. if you have created any upward dependencies), and you will be warned if and when you make code-changes that are inconsistent with the layering.
This is a new-ish feature – please email me directly and let me know how you got on or if you have questions.