He gets into lightweight containers, and how he wants a “Pay as you go” situation (sounds familiar from the debates ;).
He has a feeling that the current crop of lightweight containers are already heavy and don’t allow this.
I have to disagree. If I want to start of with a minimal system I can literally create a a container (e.g. new SomePicoContainer(), setup a Spring applicationContext) and have minimal configuration for my needs (e.g. XML config, or in code).
Then, if you find yourself wanting to add functionality you grow your configuration and start to use more functionality. You don’t have to grab the full jar files if you don’t want to (if you are worried about that). You do pay as you go.
Pico/Nano may be even better in this regard. Each project has its own goals. PicoContainer is just that. It stays lean and mean and just does the one thing. Then Nano builds on top of that. It manages trees of PicoContainers, has support for services such as Hibernate, NanoWar, etc.
I am enjoying pay as you go right now!