```
@Target({METHOD,FIELD})
@Retention(RUNTIME)
public @interface XmlIDExtension
```
Purpose: Provide a way to allow properties with XmlID annotation have different type than java.lang.String. By default, all properties annotated with XmlID annotation are restricted to have java.lang.String type.
If XmlIDExtension annotation is used, there is no restriction of used type with XmlID annotation.

Using XmlIDExtension provides way how to achieve backward compatibility with EclipseLink 2.5.x and before.

When using xml bindings with XmlID property, it has same behavior as when XmlIDExtension is used. It means that there is no need to specify XmlIDExtension in xml, because the behavior is provided by default.

See Also:

XmlID

Annotation Type XmlIDExtension