In the TreeContentProvider interface we have a void getChildren method. The javadoc says it returns the child elements but it is a void method.
When I look at the only implementation (ModelTreeContentProvider), what it does is setting elements. Therefore I suppose the method name should be setChildren (otherwise it is a bit confusing) and the javadoc should be modified.
* Returns the child elements of the given parent.
* @param parent the parent element
* @param callback the content callback
public void getChildren(Object parent, AsyncContentCallback<Object> callback);