Starting with Java 9, the rt.jar was removed, and the platform was modularized. The javax.xml.namespace.QName class moved to the module . As long as your module-info.java includes requires java.xml; , the class is available.
If you absolutely need a standalone JAR (e.g., for a very old application server or a restricted environment), you can obtain one from:
The class javax.xml.namespace.QName resides in the or the XML Binding API . javax.xml.namespace.qname jar file download
If you have landed on this page, you are likely staring at a frustrating NoClassDefFoundError or a ClassNotFoundException in your Java stack trace. The error message is specific: the Java Virtual Machine (JVM) cannot locate the javax.xml.namespace.QName class.
xml-apis-x.x.x.jar or jaxb-api.jar .
javax.xml.namespace.QName (Qualified Name) is a core class in the Java XML ecosystem. According to the W3C XML Schema specification, a QName represents a qualified XML name—essentially a combination of a , a local part , and an optional prefix .
You will need to download a separate JAR if: Starting with Java 9, the rt
You can find this JAR on Maven Central.
However, starting with Java 9 and Project Jigsaw, Java became modular. If your application is running on Java 9 or later but your module path or classpath isn't configured correctly, the system might not be resolving the java.xml module. If you absolutely need a standalone JAR (e