code: public void setContainerConfiguration(AbstractConfiguration config, String name, int index) throws IndexOutOfBoundsException {
          if (!configList.contains(config)) {
              checkIndex(index);
              containerConfigurationChanged = true;
              containerConfiguration = config;            
              addConfigurationAtIndex(config, name, index);
          } else {
              logger.warn(config + " is not added as it already exits");
          }        
      }
docs: Adds a child configuration and makes it the <em>container
  configuration</em>. This means that all future property write operations
  are executed on this configuration. Note that the current container
  configuration stays in the list of child configurations
  at its current position, but it passes its role as container
  configuration to the new one.
  
  @param config the configuration to be added
  @param name the name of the configuration to be added
  @param index index to add this configuration
  
  @throws IndexOutOfBoundsException