When people say they are a "Java & XML" developer, what do they mean? Are they saying they create XML data to be used in applications, or they use XML to configure a framework like Spring or Hibernate?
What other ways are there to use XML in a Java application?
...Are they saying they create XML data to be used in applications?...
Yes
...or they use XML to configure a framework like Spring or Hibernate?..
No, that would be Java & (Spring|Hibernate)
Each person means a different thing when they use even a single buzzword, the more buzzwords chained together the larger variation in what it could actually mean.
But:
I think that for anyone who says that they are a 'Java & XML developer' what they mean is that they have had Java projects in the past where they used XML as a data format, or a configuration mechanism, etc, and they feel comfortable enough using Java & XML that they may like to find a job where they can continue to use both.
I think they are saying they have parsed XML, generated XML, stored it, sent it over a network, done queries inside an XML document, transformed XML, etc. They know what is a well formed document and what is a valid one. They have defined validating schemas either with XML schema or DTD, and have validated documents using DTD or Schemas defined by themselves and/or others. They know what the DOM is and what is a DOM parser and a SAX parser and when to use each. They have used standard Java APIs for doing all of the above.
They have certainly edited XML with text editors and IDEs, probably also to configure Spring, Hibernate and other things but that's not what being an XML developer means.
The Java & XML dev can pass data in and out of the Java program as XML. This will include knowledge of parsers (SAX & DOM), Validation, XSL application. Since a lot of configuration(.properties),communication(xmpp,soap) and persistence is done via XML as well, scattering of knowledge in these areas will come in handy for providing examples of data passing through Java as XML. Data structures also form an integral part of XML knowledge especially trees, iterators etc.Representing the XML data in memory as an efficient data structure and modifying it is an essential skill.
I used to promote the fact that I knew XML on my resume, etc., then I realized that everyone who does development should know XML and the fact that I was promoting it was kind of stupid.