Sorry guys, I'm really ignorant, but what is the technical reason why removing unused imports is a good idea?
Simple, classloader resolution issues.
Every import causes the classloader to try to resolve a class because the loaded class may use them some time during its life. I have run into this before. If you have an import for javax.mail.Session, then you need to have that class in your classpath--even if it is never used. This is true for JDK 1.4.1 at least.
One thing that I have done in the Excalibur DataSource package is to use reflection to soften dependencies for the InformixDataSource class. Otherwise, the class will refuse to load because the Informix jars are not found. Now it catches that issue at configuration time, but the class can still be loaded at init time.
Sooner or later those imports will bite you in the butt. Esp. when one of those stale imports reflects a class that no longer exists. You will fail to compile it.
