Why and when to create a multi-module Maven project?

Question

I have a general question about Maven\'s multi module project. When and why to go for it?

Answer 1

Splitting the project into multiple modules is useful for example if the modules need to be deployed separately, or in case of a library some consumers of the project need only a subset of the classes, or the developers of the library want to make a clear distinction between what is public API and what is private implementation. And with big projects it may make the code easier to keep in order, even if it the code could technically be all in the same module.