private AssemblyContextResolver processAssemblyContextResolverTag(Element element, ParserContext parserContext) {
if (element == null) {
BeanDefinitionBuilder contextResolverBean;
contextResolverBean = BeanDefinitionBuilder.rootBeanDefinition(DefaultAssemblyContextResolver.class);
parserContext.getRegistry().registerBeanDefinition(ENVIRONMENT_CONTEXT_RESOLVER_NAME, contextResolverBean.getBeanDefinition());
return new DefaultAssemblyContextResolver();
} else {
String clazz = element.getAttribute("class");
BeanDefinitionBuilder contextResolverBean = BeanDefinitionBuilder.rootBeanDefinition(clazz);
parserContext.getRegistry().registerBeanDefinition(ENVIRONMENT_CONTEXT_RESOLVER_NAME, contextResolverBean.getBeanDefinition());
try {