CSSBox is an (X)HTML/CSS renderingengine written in pure Java. Its primary purpose is to provide a complete information about the rendered page suitable for further processing. However, it also allows displaying the rendered document.
SwingBox is a Java Swing component that allows displaying the (X)HTML documents including the CSS support. It is designed as a JEditorPane replacement with considerably better rendering results. SwingBox is pure Java and it is using the CSSBox renderingengine for rendering the documents.
dompdf - the PHP 5 HTML to PDF converter. dompdf is a (mostly) CSS compliant HTML renderingengine written in PHP. It supports external stylesheets, inline style tags, and the style attributes of individual HTML elements. Requires PHP 5.