Deserializer producing nulls instead of objects

Question

I'm using JAX RPC RI and generating my client code using the java service code, not the wsdl. In one of my test calls, I'm trying to return a custom object. One of the members of that object is an ArrayList of another type of custom object. Once the object is deserialized, the ArrayList is empty. I've also tried replacing the ArrayList with a regular array, and in that case I end up with an array of the correct length, but with all the elements null. I've snooped on the SOAP traffic (using a cool tool: http://capescience.capeclear.com/articles/using_nettool/) and the XML being returned from the service looks correct. The object looks thusly:
class ComplexA {
ArrayList _listOfBs;
public ArrayList getListOfBs() {
return _listOfBs;
public void setListOfBs( ArrayList list ) {
_listOfBs = list;
class ComplexB {
... more members
Both classes follow all the rules of JavaBeans. Also, I can correctly pass ComplexB objects. It's only when they're inside an ArrayList inside ComplexA that they get lost. I've looked at the code generated by wscompile and it looks OK. I really wish they would release the JAX RPC source. Unfortunately, I haven't been able to boil this problem down to a simple code example. Most things work, just this one problem does not.
One other thing: Running this through the debugger, I can see that the ComplexBs get constructed during deserialization, so something is breaking down when they are supposed to be added to a new ArrayList.

Answer 1

OK, I figured out what was going wrong. Part of it was the way I was testing the deserialization. Part of it was how deserialization is done.
I had assumed that when the deserializer called my setFoo( ArrayList ) method, that the List would already be populated, so I was printing the size of the list to stdout from inside setFoo and if it was 0, I was assuming it had failed. The trouble is that the deserializer does the following instead:
ArrayList newFoo = new ArrayList();
newComplexA.setFoo( newFoo );
newFoo.add( ...first item in list... );
newFoo.add( ...second item in list... );
In other words, it populates the array after it passes it to you. That's OK as long as you are saving a reference to that array. But I was using the array as a convenient way to pass the contents of my object and my setter was reading the array and populating an internal variable based on that. So when the deserializer post-populated the array, I missed out on those changes.