Exactly. And if you look at the OP's nick, you'll notice that he is the author of this blog post. As a matter of fact, if you check out his submissions (http://news.ycombinator.com/submitted?id=mainguy) you'll notice that he has a habit of submitting his blog posts to HN whenever he writes them.

Here's a message to you, mainguy: It's nice that you're blogging and all, but please, understand that not everything you write is HN-worthy.

Flagged.

There are a number of people I know who have never touched Java and are being exposed to the eco-system through languages like Clojure and Scala and this kind of overview may be useful to them.

However, I agree that it's not worthy to be on the front-page of HN.

These are not Java-specific data structures. If you already know these concepts -- and I don't see how you could write code without inevitably bumping into them -- the Java implementations should be intuitive and trivial to learn. Not to mention clearly documented.

The only reason I feel this is out of place here is because the very first thing the author says is "if you google[...]" which I would hope most hackers do before they start asking questions of others.

Especially since it's talking about old Java 1.4 collections, with no mention of changes in the last seven years!