I don’t know what’s so complicated about UML that I never seem to get it. Or I never seem to remember it. I guess I like to learn by doing. I just don’t learn by reading an article or a book. Nonetheless, you need an article to learn the concepts. Read on.
I’ve read quite a few articles about UML but I had always been confused. I even read some of UML Distilled book (chapter about class diagram) by Fowler (considered a classic intro to UML), which to me is a little vague and not specific enough. (I did like the UML User Guide, though, by Grady Booch, the original author of UML.) However, I don’t think that you really need a book to learn the class diagrams — you can learn from a good article. I am going to give you the article that it is currently my number one intro to UML’s class diagrams. It was published by The Rational Edge and was written by Donald Bell, here is the link. He breaks it very nice: simple, clear, and gradual. With good examples too. Read it, re-read it, and whenever you get a chance draw some. You’ll learn and you’ll remember. Not like me. (( But I think I’m getting it now.
Article Link: UML Basics: The class diagram by Donald Bell