ResponseEntityExceptionHandler is not getting called when exception occurs

Question

I am new to spring. I am developing a REST api with spring webmvc. For Error Handling I got this link http://docs.spring.io/spring/docs/3.2.x/spring-framework-reference/html/mvc.html#mvc-ann-rest-spring-mvc-exceptions

I have tried to use ResponseEntityExceptionHandler in my project . but whenever my controller throws exception it never reaches to this ResponseEntityExceptionHandler.

Following are my code snippet

Controller

@Controller
@RequestMapping("/hello")
public class HelloController {  
    private static final Logger logger = Logger.getLogger(HelloController.class);
    @RequestMapping(value="/{name}", method=RequestMethod.GET)
    public @ResponseBody String greet(@PathVariable(value = "name")String name ) throws InvalidInputException, ResourceNotFoundException{
        logger.info("start greet() "+name );
        System.out.println("start greet() "+name);
        String message = null;
        if("".equalsIgnoreCase(name))
        {
            throw new InvalidInputException("Invalid Input");
        }
        List<String> names = new ArrayList<String>();
        names.add("Harshal");
        names.add("Smitesh");
        if(names.contains(name)){
            message = "Hello "+ name;
        }else{
            throw new ResourceNotFoundException("Requested Resource not found");
        }
        System.out.println("end greet");
        logger.info("end greet()");
        return message;
    }
}

Exceptions

package com.practice.errorhandlerdemo.exception;

public class InvalidInputException extends RuntimeException{
    private static final long serialVersionUID = 5489516240608806490L;
    public InvalidInputException() {
        super("Invalid Input");
    }
    public InvalidInputException(String message) {
        super(message);
    }
}

package com.practice.errorhandlerdemo.exception;

public class ResourceNotFoundException extends RuntimeException {
    private static final long serialVersionUID = -4041009155673754859L;
    public ResourceNotFoundException() {
        super("requested resource not found");
    }
    public ResourceNotFoundException(String message) {
        super(message);
    }
}

exceptionhandler

@ControllerAdvice
public class RestResponseEntityExceptionHandler extends ResponseEntityExceptionHandler {
    private static final Logger logger = Logger.getLogger(RestResponseEntityExceptionHandler.class);
    @ExceptionHandler(value={ResourceNotFoundException.class})
    @ResponseStatus(value=HttpStatus.NOT_FOUND)
    protected ResponseEntity<Object> handleResourceNotFound(RuntimeException ex, WebRequest request){
        logger.info("start handleResourceNotFound()");
        String bodyOfResponse = "Requested resource does not found";
        HttpHeaders httpHeaders = new HttpHeaders();
        httpHeaders.setContentType(MediaType.APPLICATION_JSON);
        return handleExceptionInternal(ex, bodyOfResponse, httpHeaders, HttpStatus.NOT_FOUND, request);
    }

    @ExceptionHandler(value={InvalidInputException.class})
    @ResponseStatus(value=HttpStatus.BAD_REQUEST)
    protected ResponseEntity<Object> handleInvalidInput(RuntimeException ex, WebRequest request){
        logger.info("start handleInvalidInput()");
        String bodyOfResponse = "Invalid Input";
        HttpHeaders httpHeaders = new HttpHeaders();
        httpHeaders.setContentType(MediaType.APPLICATION_JSON);
        return handleExceptionInternal(ex, bodyOfResponse, httpHeaders, HttpStatus.BAD_REQUEST, request);
    }
}

dispatcher servlet

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xmlns:context="http://www.springframework.org/schema/context"
xmlns:p="http://www.springframework.org/schema/p"
xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-4.0.xsd http://www.springframework.org/schema/context  http://www.springframework.org/schema/context/spring-context-4.0.xsd">

   <context:component-scan base-package="com.practice.errorhandlerdemo.controller"/>
   <context:annotation-config/>  

</beans>

web.xml

<web-app>
    <display-name>ErrorHandlerDemo</display-name>
    <servlet>
        <servlet-name>dispatcher</servlet-name>
        <servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>
        <load-on-startup>1</load-on-startup>
        <init-param>
            <param-name>contextConfigLocation</param-name>
            <param-value>/WEB-INF/my-servlet.xml</param-value>
        </init-param>
    </servlet>
    <servlet-mapping>
        <servlet-name>dispatcher</servlet-name>
        <url-pattern>/</url-pattern>
    </servlet-mapping>
</web-app>

Answer 1

First, check that your @ControllerAdvice annotated class is taken into account by your configuration: is it located in a package that's scanned by Spring? Did you declare it as a bean in any other way?

Also, you don't need to extend ResponseEntityExceptionHandler if you don't need all the exception mappings it provides.

A simpler way to write your exception handling:

@ControllerAdvice
public class RestResponseEntityExceptionHandler {

    @ExceptionHandler(ResourceNotFoundException.class)
    protected ResponseEntity<String> handleResourceNotFound(ResourceNotFoundException ex){

      return ResponseEntity
              .status(HttpStatus.NOT_FOUND)
              .body("Requested resource does not found");
    }

    @ExceptionHandler(InvalidInputException.class)
    protected ResponseEntity<String> handleInvalidInput(InvalidInputException ex){

      return ResponseEntity
              .badRequest()
              .body("Invalid Input");
    }
}

Note that the ResponseEntity builder API has been in introduced in Spring 4.1, but you can use the regular constructor on 4.0.x.