I wrote a new refcard for Dzone, the refcard is about using XML in java and generally covers:

• What is XML
• XML usage use cases, when to use and when not to use
• what we have in Java for dealing with XML documents
• What DTD and XSD are
• How we can perform validation using XSD and DTD in different parsers
• What is different between different techniques of parsing XML documents
• Basics of XPath.
• Some performance tips

This is my second Refcard, the first refcard was about GlassFish administration and it was an instant success. An updated version of GlassFish refcarsd is published and is available at GlassFish V3 refcard. The updated version covers some new features of upcoming GlassFish v3.