@XMLRootElement versus @XmlType

jax-ws, jaxb, xml

Solution

The difference between `XmlRootElement` and `XmlType` is a matter of scoping. Remember this annotation is merely dictating the creation of the schema used to generate your XML. The `XmlRootElement` denotes a global element (with an anonymous or schema type):

<xs:element name=foo type="bar"> </xs:element> <-- schema type

while the `XmlType` is used to denote a local element (with an anonymous or complex type):

<xs:complexType name=bar> </xs:complexType> <-- complex type

The main differences in local/global here are in the hierarchy of the schema your object will appear in and whether you are declaring a schema type or complex type. The documentation for both of these annotations is well written and includes examples:

`XmlRootElement`

`XmlType`

EDIT: Addressing the `propOrder` question: you can use it on a global element if you are also declaring a local type:

@XmlRootElement (name="PersonElement")
@XmlType (propOrder={"firstname", "lastname"})
public class People{
    @XmlElement
    public String firstname;
    public String lastname;
}

This will yield something like:

<xs:element name="PersonElement" type="People"/>
<xs:complexType name="People">
    <xs:sequence>
        <xs:element name="firstname" type="xs:string"/>
        <xs:element name="lastname" type="xs:string"/>
    </xs:sequence>
</xs:complexType>

Problem

What's the difference between annotating a class with `@XMLRootElement` and `@XMLType`. I've been annotating classes with `@XMLType` when the structure will be used more than once within an XML schema and with `@XMLRootElement` when it will be used only once - is this the best approach? A different but related question which I'll include here. The `@XMLType` annotation has an propOrder attribute to specify in which order its elements appear - is there an equivalent for `@XMLRootElement`? I'm using these annotations in conjunction with JAX-WS annotations to create web services if that makes any difference.

Original source