Dynamically adding attributes without changing the java object

I want to add another new attributes the an field without changing the java

<field  attribute1 = "1"  attribute2 = "2"  attribute3 = "3"> value</filed>

@XmlRootElement(name = "field ")
public class Field 
    private String attribute1;

    private String attribute2;

    private String attribute3;

If I want to add a new attribute 4 to the XMLwithout changing the Field class(adding new field to the class and recompile).

Is there a way to do that?