code: public ParamValueType<WebAppType<T>> getOrCreateContextParam()
     {
        List<Node> nodeList = childNode.get("context-param");
        if (nodeList != null &&  nodeList.size() > 0)
        {
           return new ParamValueTypeImpl<WebAppType<T>>(this, "context-param", childNode, nodeList.get(0));
        }
        return createContextParam();
     }
docs: If not already created, a new <code>context-param</code> element will be created and returned.
  Otherwise, the first existing <code>context-param</code> element will be returned.
  @return the instance defined for the element <code>context-param</code>