International Address Formats project provides for every country in the world a java.text.MessageFormat-like format for producing text (or XML/HTML-like) representation of a given address data object appropriate for a given destination country.
Signet uses iText to stamp watermarks on PDFs. It can be used within an online order fulfillment system to place transaction details (such as the date, or buyer's name and contact info) within a PDF prior to download, to discourage copyright violation.