Not sure what about that is hard to understand, it's a convenient proxy factory bean superclass for proxy factory beans that create only singletons. Says it right there on the page.

Exactly, just like a monad is just a monoid in the category of endofunctors!

At least it's convenient...

But it's kind of disturbing that the class name is hiding that convenience from us. How are we supposed to know that it is not an inconvenient...?

It all starts getting really weird with Spring Data interfaces: a whole DSL written in camelcased method names, as if Spring deliberately turned a joke into a feature.