Question

I am new to java (coming from c#.net background) and was trying the above example to marshal and unmarshal.

Following the link below
Marshalling a List of objects implementing a common interface, with JaxB

using the above technique as mentioned by Mr.Blaise Doughan, I was able to marshal the java objects to xml. But when i save this xml and try to unmarshal the xml back to java object i get the following on the console:

com.sun.xml.internal.bind.v2.runtime.IllegalAnnotationsException: 2
counts of IllegalAnnotationExceptions
@javax.xml.bind.annotation.XmlElementRef annotation is found on two
places; one would be suffice. this problem is related to the following
location: at @javax.xml.bind.annotation.XmlElementRef(name=##default,
required=true, type=class
javax.xml.bind.annotation.XmlElementRef$DEFAULT, namespace=) at public
java.util.List Community.getPeople() at Community this problem is
related to the following location: at
@javax.xml.bind.annotation.XmlElementRef(name=##default,
required=true, type=class
javax.xml.bind.annotation.XmlElementRef$DEFAULT, namespace=) at public
void Community.setPeople(java.util.List) at Community ….

Note : I have created getters/setters for Class Boy and Class Girl for implementing unmarshalling.

Answer 1

It appears that you may have annotated both the getPeople and setPeople methods. JAXB (and other Java EE technologies) only require you annotate one.

public class Community {

    private List<Person> people;

    @XmlElementRef
    public List<Person> getPeople() {
        return people;
    }

    public void setPeople(List<Person> people) {
        this.people = people;
    } 

}

For More Information

• http://blog.bdoughan.com/2010/11/jaxb-and-inheritance-using-substitution.html
• http://blog.bdoughan.com/2011/06/using-jaxbs-xmlaccessortype-to.html