Apache XML Graphics Commons is a library that consists of several reusable components used by Apache Batik and Apache FOP. Many of these components can easily be used separately outside the domains of SVG and XSL-FO. You will find components such as a PDF library, an RTF library, Graphics2D implementations that let you generate PDF and PostScript files, and much more.
RenderX XEP is a commercial-grade application written in Java for dynamic rendering of XML documents. XEP is a pluggable architectural component that takes two open standard inputs, XML data and XSL FO stylesheet, and produces the industry's defacto standards for high-quality rendered electronic documents, Adobe PDF and PostScript. XEP supports many extensions to the XSL FO specification, including SVG graphics and PDF-to-PDF linking.
xmlroff is a fast, multilingual, multi-platform XSL formatter that transforms XSL-FO documents (or any XML with an appropriate XSL stylesheet) into PDF or PostScript. It aims to excel at DocBook formatting, and it integrates easily with other programs and with scripting languages.