[java] Is there a Java API that can create rich Word documents?

I have developed pure XML based word files in the past. I used .NET, but the language should not matter since it's truely XML. It was not the easiest thing to do (had a project that required it a couple years ago.) These do only work in Word 2007 or above - but all you need is Microsoft's white paper that describe what each tag does. You can accomplish all you want with the tags the same way as if you were using Word (of course a little more painful initially.)