How to resolve whitelabel error page in the spring boot application?

The Whitelabel Error Page is Spring Boot's default error page that appears when an exception occurs and no custom error handling mechanism is configured. It is commonly seen for issues such as incorrect URL mappings, missing resources, or unhandled exceptions.

Key Points: • The most common reason for a Whitelabel Error Page is an invalid URL or missing controller mapping. • Proper exception handling using @ControllerAdvice improves error management and user experience. • Custom error pages can replace the default Whitelabel page in production applications.

Example: Suppose a user accesses:

http://localhost:8080/products

But the application only contains:

@GetMapping("/product")

Since no matching endpoint exists, Spring Boot displays the Whitelabel Error Page with HTTP 404 status.

Common Causes and Solutions:

1. Invalid URL Mapping

Problem: • Request URL does not match any controller endpoint.

Solution: • Verify @RequestMapping, @GetMapping, or @PostMapping annotations.

Example:

@RestController
@RequestMapping("/users")
public class UserController {

    @GetMapping("/{id}")
    public User getUser() {
        return user;
    }
}

2. Missing Controller Annotation

Problem: • Spring does not detect the controller bean.

Solution: • Add:

@Controller
or
@RestController

3. Unhandled Exceptions

Problem: • Runtime exceptions are not properly handled.

Solution: • Use global exception handling.

Code Example:

@ControllerAdvice
public class GlobalExceptionHandler {

    @ExceptionHandler(Exception.class)
    public ResponseEntity<String> handleException(
            Exception ex) {

return ResponseEntity .status(HttpStatus.INTERNAL_SERVER_ERROR)

                .body("Something went wrong.");
    }
}

4. Missing View Template

Problem: • JSP, Thymeleaf, or HTML file does not exist.

Example: Controller returns:

return "home";

But:

home.html

is missing from templates folder.

Solution: • Ensure the view exists in the correct location.

5. Disable Whitelabel Error Page

Configuration:

server.error.whitelabel.enabled=false

This disables the default Spring Boot error page.

6. Create Custom Error Page

Create:

src/main/resources/templates/error.html

Spring Boot automatically displays this page when an error occurs.

Example:

404.html
500.html
error.html

Benefits: • Better user experience. • Professional appearance. • Customized error messages.

7. Check Application Logs

Logs often contain the exact reason for the failure.

Common Errors: • NullPointerException • BeanCreationException • NoHandlerFoundException • TemplateInputException

Real-World Example:

User requests:

/api/orders/100

Application throws:

OrderNotFoundException

Instead of showing the Whitelabel page, the application returns:

{ "message": "Order not found", "status": 404 }

Best Practices:

• Use @ControllerAdvice for global exception handling. • Create custom error pages for production environments. • Validate all URL mappings. • Monitor application logs regularly. • Return meaningful error responses for REST APIs.

Interview Tip: A concise interview answer is: The Whitelabel Error Page appears when Spring Boot encounters an error and no custom error handling is configured. It is commonly caused by incorrect URL mappings, missing views, or unhandled exceptions. It can be resolved by fixing controller mappings, implementing global exception handling using @ControllerAdvice, and creating custom error pages for better user experience.