I really like the Spring Framework inversion of control (or dependency injection) container. I restructured a small part of the codebase 6 months ago to use it and got chewed out for checking that in. That code didn't get reverted, though.

For modular code, what people where I work do is to write a factory class that does Class.forName(), and then Class.newInstance(). There are numerous factory classes with a single method doing the Class.forName() and Class.newInstance() thing. Spring eliminates that. Plus, the objects built up by Spring are all configured by dependency injection. I don't think many people where I work here really get that, though.