code: public ViewDescriptor getViewDescriptor(String viewName) {
  
          Assert.notNull(viewName, "viewName");
  
          try {
              return (ViewDescriptor) applicationContext.getBean(viewName, ViewDescriptor.class);
          }
          catch (NoSuchBeanDefinitionException e) {
              return null;
          }
  
      }
docs: Returns the view descriptor with the given identifier, or null if no such bean definition
  with the given name exists in the current application context.
  
  @param viewName The bean name of the view descriptor that is to be retrieved from the
  underlying application context. Must not be null.
  
  @throws IllegalArgumentException if {@code viewName} is null.
  @throws org.springframework.beans.factory.BeanNotOfRequiredTypeException if the bean retrieved from the underlying application
  context is not of type {@link ViewDescriptor}.