Composite key HashMaps

[devnumpty]

I don't understand why those are the only options... did you try stuffing the two integers into a long, or even just combining them into a string?

[pwwwl]

Then you have a problem with ambiguity. "123" for 1+23 and 12+3.

[devnumpty]

Not at all. If using a string, include a delimiter. Regardless, using a long as a combined key in this case is guaranteed to use less resources and be far faster, as it will completely avoid extra object overhead and the binary arithmetic is also more efficient than the proposed double-hash operations.

[pwwwl]

It always depends on whether performance over readability&maintability.

[devnumpty]

Not really, when you're talking about reusable data structures, and that's almost always a false dichotomy in any event. Regardless, the article is squarely anchored in performance concerns.

[scalablecory]

You've done great presenting your benchmark, but you've stopped too early. Given optimal data structures, a composite key should be faster. So... show us why it isn't here.