If you use PD4ML in Java desktop application or with Java Servlet, than you need pd4ml.jar (or pd4ml_demo.jar) and a third-party library developed by CSS Parser open-source project ss_css2.jar, which can be found in lib/ subdirectory of PD4ML distribution package.

If you plan to use PD4ML in JSP as JSP tag library, than you need in addition to the main pd4ml.jar to install pd4ml_tl.jar (pd4ml_tl_demo.jar) and pd4ml.tld files. The files can be found in the sample web application directory structure in taglib/WEB-INF/lib and taglib/WEB-INF/tlds.