[jfengel]

Assuming you have Java installed. And it's on the path.

That may not sound like much, but it's the kind of thing that is incredibly hard to figure out if you don't know what the problem is. Command lines are kind of unforgiving. When something is missing, the errors are often unhelpful. And if your next crack at it doesn't work, you get the identical error.

Googling stackoverflow isn't going to help, either.

This isn't supposed to be a major challenge. But it can really throw off a beginner. And even an experienced developer will feel stupid to have to say, "Sure, I can program in 30 languages, but I don't know how to install the FooLang compiler."