Is @XmlElement necessary for Jaxb
No, by default a JAXB (JSR-22@) implementation will treat all public fields and properties (get/set combinations) as mapped (not requiring the @XmlElement annotation).
If you wish to annotate a field I would recommend annotating your class with @XmlAccessorType(XmlAccessType.FIELD)
According to this http://jersey.java.net/nonav/documentation/latest/json.html#json.jaxb.approach.sectionYou should have this annotation (I'm also using it in my code, even though it XML oriented, but it gives me cool JSON also)
Taking this approach will save you a lot of time, if you want to easily produce/consume both JSON and XML data format. Because even then you will still be able to use a unified Java model. Another advantage is simplicity of working with such a model, as JAXB leverages annotated POJOs and these could be handled as simple Java beans.
A disadvantage of JAXB based approach could be if you need to work with a very specific JSON format. Then it could be difficult to find a proper way to get such a format produced and consumed. This is a reason why a lot of configuration options are provided, so that you can control how things get serialized out and deserialized back.
Following is a very simple example of how a JAXB bean could look like.
Example 5.3. Simple JAXB bean implementation
@XmlRootElement public class MyJaxbBean { public String name; public int age; public MyJaxbBean() {} // JAXB needs this public MyJaxbBean(String name, int age) { this.name = name; this.age = age; } }