 program elements: 
 <ul> 
   <li> a JavaBean property </li>
   <li> non static, non transient field </li>
 </ul>
 
 <p>See "Package Specification" in jakarta.xml.bind.package javadoc for
 additional common information.</p>

 The usage is subject to the following constraints:
 <ul> 
   <li> At most one field or property in a class can be annotated
        with <code>@XmlID</code>.  </li>
   <li> The JavaBean property's type must be <code>java.lang.String</code>.</li>
   <li> The only other mapping annotatio