code: @SuppressWarnings({ "rawtypes", "unchecked" })
  	protected void applyInitializers(ConfigurableApplicationContext context) {
  		for (ApplicationContextInitializer initializer : getInitializers()) {
  			Class<?> requiredType = GenericTypeResolver.resolveTypeArgument(
  					initializer.getClass(), ApplicationContextInitializer.class);
  			Assert.isInstanceOf(requiredType, context, "Unable to call initializer.");
  			initializer.initialize(context);
  		}
  	}
docs: Apply any {@link ApplicationContextInitializer}s to the context before it is
  refreshed.
  @param context the configured ApplicationContext (not refreshed yet)
  @see ConfigurableApplicationContext#refresh()