Oh, I absolutely understand why it is interesting and fast: what I don't understand is how it satisfies the rules, as it is effectively "some random project with a hashtable". Is this particular one so famous that it should be allowed instead of java.util.HashMap? Can I just publish my C++ hashtable and then rely on it, in which case the rule makes no sense? That's why I tack on "?!".
This entire subthread is clearly a digression ;p, but why do you say that? The rules were about using a built-in or standard collection: this Java implementation does not use HashMap and instead uses a random project with a better data structure for this use case. This is a loophole to bypass the restriction on writing your own hashtable: you just have to publish it first? ;P
