code: protected ResourceAdapterMBeanImpl setResourceAdapterChild(String key, ResourceAdapterMBeanImpl ra) {
          return raMBeanChildrenList.put(key, ra);
      }
docs: setResourceAdapterChild add a child of type ResourceAdapterMBeanImpl to this MBean.
  
  @param key the String value which will be used as the key for the ResourceAdapterMBeanImpl item
  @param ra the ResourceAdapterMBeanImpl value to be associated with the specified key
  @return The previous value associated with key, or null if there was no mapping for key.
  (A null return can also indicate that the map previously associated null with key.)