XMLJ is a Java XML Editor and validator project.
X3D is the open-standard format for 3D graphics scenes on the Web.
EasyML serialization library, to and from XML, similar to Gson
eXist-db is a feature rich Open Source native XML database
Simulatoralive's Java libraries and programs
NO LONGER MAINTAINED
File validation and characterization
Modabi is a Modular Data Binding system for Java
LGPL GML parser
Data migration/conversion library based on STX and XSLT transformation
A Java adapter for the NextBus Public XML Feed Service
Web-based editor for the Gateway Description Language (GDL).