#ResponseBody is not returning String message to error, throwing 404 WhiteLabel error page - spring

Question

I am following a tutorial on Spring MVC and my project is not working as expected. I am using #ResponseBody to return a string message but it is throwing a whitelabel error page. I have scoured the Internet for last 2 days but still clueless about what could I possibly do wrong. Can anybody throw some light upon this?
Spring Framework boot : 2.5.4, Java version : 11
Code snippet for LoginController :
package com.in28minutes.springboot.web.controller;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestMethod;
import org.springframework.web.bind.annotation.ResponseBody;
#Controller
public class LoginController {
#RequestMapping(value="/login", method=RequestMethod.GET, produces="text/plain")
#ResponseBody
public String loginMessage() {
return "Hello World";
}
}
2021-09-10 15:33:54.158 DEBUG 8556 --- [nio-8080-exec-1] o.s.web.servlet.DispatcherServlet : GET "/login", parameters={}
2021-09-10 15:33:54.158 DEBUG 8556 --- [nio-8080-exec-1] o.s.w.s.handler.SimpleUrlHandlerMapping : Mapped to ResourceHttpRequestHandler [Classpath [META-INF/resources/], Classpath [resources/], Classpath [static/], Classpath [public/], ServletContext [/]]
2021-09-10 15:33:54.160 DEBUG 8556 --- [nio-8080-exec-1] o.s.w.s.r.ResourceHttpRequestHandler : Resource not found
2021-09-10 15:33:54.160 DEBUG 8556 --- [nio-8080-exec-1] o.s.web.servlet.DispatcherServlet : Completed 404 NOT_FOUND
2021-09-10 15:33:54.160 DEBUG 8556 --- [nio-8080-exec-1] o.s.web.servlet.DispatcherServlet : "ERROR" dispatch for GET "/error", parameters={}
2021-09-10 15:33:54.161 DEBUG 8556 --- [nio-8080-exec-1] s.w.s.m.m.a.RequestMappingHandlerMapping : Mapped to org.springframework.boot.autoconfigure.web.servlet.error.BasicErrorController#errorHtml(HttpServletRequest, HttpServletResponse)
2021-09-10 15:33:54.177 DEBUG 8556 --- [nio-8080-exec-1] o.s.w.s.v.ContentNegotiatingViewResolver : Selected 'text/html' given [text/html, text/html;q=0.8]
2021-09-10 15:33:54.178 DEBUG 8556 --- [nio-8080-exec-1] o.s.web.servlet.DispatcherServlet : Exiting from "ERROR" dispatch, status 404
#SpringBootApplication
public class SpringBootFirstWebApplication {
public static void main(String[] args) {
SpringApplication.run(SpringBootFirstWebApplication.class,
args);
}
}

Answer 1

I will guess that your SpringBootFirstWebApplication is not placed in the parent package of all other packages in your application and therefore #Controller annotation in LoginController is not scanned.
If that is the case, change SpringBootFirstWebApplication to the parent package of all other packages in your application.

Answer 2

It seems like your requested URL in #RequestMapping is wrong. Your expected URL is value="/home", but your actual is value="/login"