[ollysb]

There really isn't much difference between using a bootstrapper class or a spring xml file, they're still both configuration files and should be equally convenient to maintain.

One of the advantages spring gives you in your scenario is multiple options for configuring your app. So in your case you can use annotations for parts of the app that don't change and then specify the parts that are different for each customer using xml(I seem to recall you might even be able to wire up a spring container using vanilla java).

Spring actually brings a lot more to the table, properly qualifying it as an IOC container. It offers mechanisms for applying cross-cutting aspects such as transaction and security management.