JSDAI is a toolkit for STEP (ISO 10303), the STandard for the Exchange of Product Model data, that enables linking of CAD, CAM, PDM, PLM, CAx systems. JSDAI supports the development of Express data models (ISO 10303-11) and their implementation in Java.
XML Document Validator is a Java implementation of CLiXML - Constraint Language in XML - that allows to express complex constraints about XML content using a mixture of first order logic and XPath.