An interesting project on SourceForge: JXWB and WWE. WWE is an HTML4/CSS2-compliant HTML renderer kit for Java. The description of WWE:
This is the final release of WWE 1.0. It is an implementation of an HTML editor pane and kit providing Java Swing developers with an HTML renderer/editor that supports W3C's latest specifications for HTML and CSS. This release is slightly premature in that it has been repackaged from a commerical project and as such isn't as clean as can be expected. Another release will be forth coming addressing this issue as well as providing documentation.