If PDF files are included using pdfTeX, PDF annotations are stripped. The Pax project offers a solution without altering pdfTeX. A Java program (pax.jar) parses the PDF file that will later be included. The program then writes the data of the annotations into a file that can be read by TeX. The LaTeX package pax extends the graphics package to support the scheme: if a PDF file is included, the package looks for the file with the annotation data, reads them and puts the annotations in the right place.