code: @Override
      public void addProperty(String key, Object value) {
          containerConfiguration.addProperty(key, value);
      }
docs: Add the property with the <em>container configuration</em>.
  <b>Warning: </b>{@link #getProperty(String)} on this key may not return the same value set by this method
  if there is any other configuration that contain the same property and is in front of the
  <em>container configuration</em> in the configurations list.