I just found an interesting case that we should probably validate and fail.

public class BaseClass
{
 @XmlAttribute(name="something");
 public void setSomething(String value) {}
}

public class MyClass extends BaseClass
{
 @XmlAttribute(name="something")
 public void setSomethingElse(String value) {}
}

I gues which one gets used depends upon the order they appear
in the properties retriefved from BeanInfo?
But this should really be an error. You should have to do:

public class MyClass extends BaseClass
{
 @XmlTransient
 public void setSomething(String value) { super.setSomething(value); }

 @XmlAttribute(name="something")
 public void setSomethingElse(String value) {}
}

The same issue probably exists for properties on the same class
and elements as well?