Peter Eastman has posted the first beta of Buoy 1.0, a public domain "library for creating user interfaces in Java programs. It is built on top of Swing, but provides a completely new set of classes to represent graphical components." Among other features, Buoy can serialize user interfaces as XML. Java 1.4 or later is required.
Aspect Security has posted the first alpha of Stinger, an open source "HTTP request validation engine based on regular expressions for use in J2EE (servlet and JSP) environments. Developers specify simple rules in an XML format called Security Validation Description Language (SVDL0 and Stinger applies them to requests. The philosophy of Stinger is to provide developers with all the information they might need about what went wrong and let them take the appropriate action." Stinger uses XOM to manage the XML. Stinger is published under the LGPL.