No editing - you compile the .java file which results in a .class file. The IDE does that for you, but it's possible it doesn't put the class files where they need to be. But after compilation they should be somewhere in the project folder, provided there were no errors.
Start by defining what the output should be. PDF and XLS are very different file formats, which lead to very different ways you can use them. Do you want something to print? Then PDF would seem to the medium of choice. Do you want something to edit? That would rule out PDF.
Indeed, I think a library such as Unity would be way overkill for your purposes. In Android you could subclass an android.view.View and use a Canvas to do custom drawing (which includes putting text on the canvas if need be).