In a recent article on Hacker News regarding the evils of classes, one of the valid uses of classes were for makeshift namespaces. I would have to agree with this. The model of Java requires all functions to be inside classes. If you have a class full of statics, it functionally becomes a unique namespace. It's semantics, but at that point, they're interchangeable.
Except that you can't import a class using "using" or "import", so you have to write Math.cos() everywhere.
EDIT: I see below that Java has added "import static", but at that point you're in the situation where you have two things that are almost the same but not quite, which is not a particularly clean design in my opinion.
