A JDOM developer uses the Java-based JDOM (Java Document Object Model) library to easily manipulate and interact with XML data in Java applications. They create, read, modify, and write XML documents, handling XML data structures in a more intuitive and straightforward way than using the standard Java XML APIs. They also work with namespaces, attributes, text content, and child elements, and handle XML parsing and output. Their role often includes troubleshooting and improving the efficiency of XML data handling, ensuring seamless integration of XML data with Java applications. They often collaborate with other developers in building and maintaining software applications.