Don't give me static...
I was just burned pretty bad by a subtle bug and want to share some general thoughts with
folks. The core of the issue that I had was that the Config class (which is not static)
held a static map that represents the internal state of the object. Additionally, this
static map was only initialized upon the first creation of a Config object. This
doesn't really cause much harm in a deployed environment, but it caused a lot of pain
in our unit test suite -- specifically why one of the tests would pass when run by itself,
and yet failed when run in the larger test suite.
So I think that the lesson learned is: Don't use static anything. Or, at the very
least, treat static classes/variables as a code smell, and really try to justify it before
throwing it in. One of the really nice aspects of Guice is its ability to abstract away
how the dependencies of a component are created, and I think we should defer to the
framework for e.g. creating objects as singletons for optimization purposes.
What do you guys think? Am I overreacting? :)
- Justin