java - Polymorphism in JAX-RPC web services -

i have jax-rpc (java) web service needs return complex polymorphic value. more specific, class structure this:

abstract class child { }  class question extends child {     private string name;     // other fields, getters, , setters }  class section extends child {     private string label;     private child[] children;     // getters , setters }  class quiz {     private child[] elements;     // getter , setter } 

my web service has method returns quiz, of course may contain questions , sections may contain questions , other sections, , on , forth. however, when generate wsdl, child , quiz make in. when call web service, quiz element right number of children, they're child elements, , they're empty.

is there way make work, short of returning xml string?

before asks, due circumstances beyond control, cannot use jax-ws.

i don't think jax-rpc supports polymorphism in way. had similar problem, , had work around creating class had 2 members - 1 each of 2 classes possibly returned - , populating 1 depending on type wanted return. in case:

class child  {     private section section;     private question question;     // constructor, etc... }  class question  {     private string name;     // other fields, getters, , setters }  class section  {     private string label;     private child[] children;     // getters , setters }  class quiz  {     private child[] elements;     // getter , setter } 

which requires client check member of child populated, , horribly ugly, know.