Please post a little more information about what you are trying to do and maybe some code if you've attempted to write if any and you'll have a better shot at getting some help IMHO. I dont know for example from your question if you are trying to tie into a scanner or if you are reading the contents of a file using FileInputStream or what
actually, you do have to read the content of the document if you expect to display it in a viewer.
I agree with the last post that we dont really have much information, but that said, my guess is that you'll need to study the Java2D API and use the code approach you find there to create an image based on the bytes that you read from the scanner. Then, add that image to a JPanel or whatever in your application.