Simplified Modularization of a Java Web Project
Complete post (in portuguese): http://blog.jesjobom.com/2015/12/modularizacao-simplificada-de-projeto-web/
The main idea here is to have a single project with multiple modules and specialization of modules to serve multiple clients. So any generic improvement will affect all clients, still allowing to work on specific implementations.
This is not a hot swap between modules solution!