Parsers

Microsoft XML Parsers for Microsoft's IE4
   Netscape Demo of XML Parser in Java
   Datachannel XML Tools

Sun's HTML Parser
   It may not that perfect. (Only for HTML, not all SGML features)

Class Parser of Swing
   javax.swing.text.html.parser.Parser
   This may parse only SGML/HTML.

Clyde Virtual University's web-site HTML parser
Caucho XML Parser
   This is part of resin 1.0
HEX - The HTML Enabled XML Parser(Hewlett Packard)
   An HTML parser. It doesn't understand either SGML or XML DTD's...
SwTech's XML Parsers and Development Tools
   This page also has a list of parsers.
IBM's XML Parser for Java
Supporting XML, DOMHash, and DOM.
StudioM's XML Parser for Java