Anything is copyable. You can only try to make it as hard as possible. For example: convert it to a non-editable, non selectable PDF (But a PDF can be cracked). Or show it as an image (but that can be read with OCR). Or create a JFrame that holds a JTextArea, that you create that it cannot be selected (But after a print-screen, I can run that through OCR as well)


My point is, if you don't want your stuff to be copied, don't publish it. Otherwise it's possible in one way or the other. What makes your document so special that is not allowed to copy?