Yes, most of the material is still very much applicable. Essentially it boils down to a collection of really good collections that makes your Java code more maintainable.

I think it is still current, and is a decent read. Like, you should know these things, but not necessarily adhere to them. I spent a decade believing in OOP. Lately, my thoughts have changed. Unless you really need to track non-global state, or need a namespace in a language that doesn't have namespaces, I don't think you need to go down the OOP route as far as Mr. Bloch advocates. Sometimes a simple function just gets the job done, clearly and effectively.