We are getting an unexpected 'nillable="true"' in generated WSDL when using List

Issue

We have a web service that we expose from an EJB, a web method returns a object that contains collections like this:

public class Picture {
  List<Person> buyers;
  List<MyColor> colors;

  public List<Person> getBuyers() {return buyers;}
  public List<MyColor> getColors(){return colors;}
  …
}

The wsdl generated contains the following for the class Picture

<xs:complexType name="picture">
  <xs:sequence>
    <xs:element maxOccurs="unbounded" minOccurs="0" name="buyers" nillable="true" type="tns:person"/>
    <xs:element maxOccurs="unbounded" minOccurs="0" name="colors" nillable="true" type="tns:myColor"/>
  </xs:sequence>
</xs:complexType>

As you can see both of the collection are generated with nillable="true" where we expect @XMLElement defaults be applied:

public @interface XmlElement {
    boolean nillable() default false;
    …
}