How would you modularize a large application that has some incoming (SOAP) webservices, some outgoing webservices, transformations between them and internal formats, internal logging services, accesses external archiving webservices, delays stuff and works on this asynchronously and so forth?

One way is to split the functionality into a collection of WAR, deploy all of them on one application server and have them communicate with internal webservices. This has some overhead, especially if the messages are large, and you might run into performance problems due to thread count restrictions and so forth.

Another way would be to put everything into a giant WAR, such that you can communicate directly. Not exactly modularization. What would you do?