[scorchin]

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.

[snikolic]

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.

[TheCapn]

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.