Dawid, I find that I didn't quite answer all of your questions, and then again maybe I'm not in a position to.
I started this by looking for some way to get the functionality of Trove without the GPL. When I discovered that Mahout had already absorbed Colt, I decided that the shortest path was to start from there. I looked into planting this in commons-collections, but it was not so easy. Colt collections depend on some scalar math code (random numbers, etc). The commons-math people have a very high bar for contributions, and the process of factoring out the math substrate, comparing it to commons math, identifying the delta, contributing it to math, etc, etc, was beyond my personal resources. If you've got a foundation member at hand, collections will make you a sandbox to facilitate the contribution. Much as I'm enjoying myself at this, I certainly won't be offended if Mahout throws it all out in favor of what you've got there. One issue for Mahout is that it is using some above-collections functionality from Colt that will take very careful modification to use your (or any other) alternative. --benson
