Marshal annotated objects that are part of the body
20.2. Using JAXB with the Atom Provider The org.jboss.resteasy.plugins.providers.atom.Content class allows you to unmarshal and marshal JAXB annotated objects that are the body of the content. Here's an example of sending an Entry with a Customer object attached as the body of the entry's content. @XmlRootElement(namespace = "http://jboss.org/Customer") @XmlAccessorType(XmlAccessType.FIELD) public class Customer { @XmlElement private String name; public Customer() { } public Customer(String name) { this.name = name; } public String getName() { return name; } } @Path("atom") public static class AtomServer { @GET @Path("entry") @Produces("application/atom+xml") public Entry getEntry() { Entry entry = new Entry(); entry.setTitle("Hello World"); Content content = new Content(); content.setJAXBObject(new Customer("bill")); entry.setContent(content); return entry; } } The Content.setJAXBObject() method is used to tell the content object you are sending back a Java JAXB object and want it marshalled appropriately. If you are using a different base format other than XML, i.e. "application/atom+json", this attached JAXB object will be marshalled into that same format.