Spring boot rest : Circular view path [error]: would dispatch back to the current handler URL [/error] again - spring-boot

Question

My issue is I get 404 error when calling the spring boot application on localhost:8080/users
package com.myproj.users.controller;
import java.nio.file.attribute.UserPrincipalNotFoundException;
import java.security.Principal;
import java.util.concurrent.atomic.AtomicLong;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.PathVariable;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestMethod;
import org.springframework.web.bind.annotation.RequestParam;
import org.springframework.web.bind.annotation.ResponseBody;
import org.springframework.web.bind.annotation.RestController;
import com.myproj.users.Greeting;
import com.myproj.users.PhysicalCharacteristicsRepository;
import com.myproj.users.UserRepository;
import com.myproj.users.UserResource;
#RestController
#RequestMapping("/users")
public class UserRestController {
private UserRepository userRepository;
private PhysicalCharacteristicsRepository characteristicsRepository;
#RequestMapping(value = "/greeting/", method = RequestMethod.GET)
public String greeting() throws UserPrincipalNotFoundException {
return "Greeting";
}
#RequestMapping(value = "/error/")
public String error() {
return "Error handling";
}
private static final String template = "Hello, %s!";
private final AtomicLong counter = new AtomicLong();
#RequestMapping(method = RequestMethod.GET)
public #ResponseBody Greeting sayHello(#RequestParam(value = "name", required = false, defaultValue = "Stranger") String name) {
return new Greeting(counter.incrementAndGet(), String.format(template, name));
}
#Autowired
UserRestController(UserRepository userRepository, PhysicalCharacteristicsRepository characteristicsRepository) {
this.userRepository = userRepository;
this.characteristicsRepository = characteristicsRepository;
}
}
package com.myproj.users.controller;
import java.nio.file.attribute.UserPrincipalNotFoundException;
import org.springframework.hateoas.VndErrors;
import org.springframework.http.HttpStatus;
import org.springframework.web.bind.annotation.ControllerAdvice;
import org.springframework.web.bind.annotation.ExceptionHandler;
import org.springframework.web.bind.annotation.ResponseBody;
import org.springframework.web.bind.annotation.ResponseStatus;
import com.weather.exceptions.UserNotFoundException;
#ControllerAdvice
class UserControllerAdvice {
#ResponseBody
#ExceptionHandler(UserNotFoundException.class)
#ResponseStatus(HttpStatus.NOT_FOUND)
VndErrors userNotFoundExceptionHandler(UserNotFoundException ex) {
return new VndErrors("error", ex.getMessage());
}
#ResponseBody
#ExceptionHandler(UserPrincipalNotFoundException.class)
#ResponseStatus(HttpStatus.NOT_FOUND)
VndErrors userPrincipalNotFoundException(UserPrincipalNotFoundException ex) {
return new VndErrors("error", ex.getMessage());
}
}
package com.myproj.users;
public class Greeting {
private final long id;
private final String content;
public Greeting(long id, String content) {
this.id = id;
this.content = content;
}
public long getId() {
return id;
}
public String getContent() {
return content;
}
}
I have tested the spring project in https://spring.io/guides/gs/actuator-service/ and it worked so I ignore what's going on.

Answer 1

I have defined a controller to manage errors. I have copied it from Spring Boot Remove Whitelabel Error Page
The new Application class is the following :
package com.test;
import org.apache.log4j.LogManager;
import org.apache.log4j.Logger;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.EnableAutoConfiguration;
import org.springframework.boot.autoconfigure.domain.EntityScan;
import org.springframework.context.annotation.ComponentScan;
import org.springframework.context.annotation.Configuration;
import org.springframework.data.jpa.repository.config.EnableJpaRepositories;
#Configuration
#ComponentScan(basePackages = "com.test")
#EnableAutoConfiguration
#EnableJpaRepositories(basePackages = "com.test")
#EntityScan(basePackages = "com.test")
public class Application {
static final Logger logger = LogManager.getLogger(Application.class.getName());
public static void main(String[] args) {
logger.debug("Entered the application");
SpringApplication.run(Application.class, args);
}
private Application() {
}
}
As you can see I have added a controller in ComponentScan as follows :
#ComponentScan(basePackages = "com.test")
#EnableJpaRepositories(basePackages = "com.test")
#EntityScan(basePackages = "com.test")
To test I used curl curl http://localhost:9002/eleves/Hammami/ and firefox.

Answer 2

Changing #Controller to #RestController solved my issue.
In my case I was using thymeleaf(MVC), after that I switched to pure backend.