How do I learn to use Java commons-collections?

Question

Weird title, I know, let me explain.

I am a developer most familiar with C# and Javascript. I am completely sunk into those semi-functional worlds to the point that most of my code is about mapping/reducing/filtering collections. In C# that means I use LINQ just about everywhere, in Javascript it's Underscore.js and jQuery.

I have currently been assigned to an ongoing Java project and am feeling rather stifled. I simply do not think in terms of "create an array, shuffle stuff from one to another". I can (and did) create my own versions of the main map/reduce functions using anonymous types implementing interfaces but why re-invent the wheel? The project I am currently on already has commons-collections-3.1.jar and looking through the classes contained it seems like it likely can do everything that I want and more.

For the life of me, I can't find how to actually use it. Looking through the dozens of classes therein is not very helpful and the only thing I can google up is the api doc which is equally as helpful.

How do you use it to Map/Select, Filter/Where, Reduce/Aggregate? Is there anywhere that gives an actual tutorial on this library?

Answer 1

(Comment as answer for formatting purposes.)

Not so much, other than the limited user guide.

That said, I'm not sure where specifically you're having problems--filtering and selecting is mostly wrapped up in the functors package, and utilized by the CollectionUtils class.

While you're not looking for a replacement, you might find things like Guava or Lambda4J a bit more similar to what you're used to (within Java's constraints), and they're a bit less verbose.