This application has no explicit mapping for /error, so you are seeing this as a fallback 404

在这里，"This application has no explicit mapping for /error, so you are seeing this as a fallback" 的意思是应用程序没有显式地将 /error 进行映射，所以你会看到它作为一种备选方案。通常，这种情况下会返回一个404错误，表示所请求的资源不存在。