1e:T4d0,```markdown To handle exceptions in Spring Boot, you can use the `@ControllerAdvice` annotation along with `@ExceptionHandler` to define global exception handling logic. Below is an example of how to implement a global exception handler: ```java @ControllerAdvice public class GlobalExceptionHandler { @ExceptionHandler(ResourceNotFoundException.class) public ResponseEntity handleNotFound(ResourceNotFoundException ex) { return new ResponseEntity<>(ex.getMessage(), HttpStatus.NOT_FOUND); } @ExceptionHandler(Exception.class) public ResponseEntity handleGeneral(Exception ex) { return new ResponseEntity<>("Something went wrong: " + ex.getMessage(), HttpStatus.INTERNAL_SERVER_ERROR); } } ``` ### Explanation: - **@ControllerAdvice**: This annotation allows you to handle exceptions across the whole application in one global handling component. - **@ExceptionHandler**: This annotation is used to define methods that handle specific exceptions. - `handleNotFound`: Handles `ResourceNotFoundException` and returns a `404 Not Found` response with the exception message. - `handleGeneral`: Catches all other exceptions and returns a `500 Internal Server Error` response with a generic error message. ```1f:T44a,# What is Spring Boot Actuator, and how is it used? ## How to Enable Actuator in Spring Boot ### Add Dependency (Maven) ```xml org.springframework.boot spring-boot-starter-actuator ``` ### Enable Endpoints in `application.properties` or `application.yml` ```properties management.endpoints.web.exposure.include=health,info,metrics management.endpoint.health.show-details=always ``` You can use `*` to expose all endpoints (not recommended in production): ```properties management.endpoints.web.exposure.include=* ``` ## Accessing Actuator Endpoints By default, endpoints are available under `/actuator`: - [http://localhost:8080/actuator/health](http://localhost:8080/actuator/health) - [http://localhost:8080/actuator/metrics](http://localhost:8080/actuator/metrics) - [http://localhost:8080/actuator/info](http://localhost:8080/actuator/info) ## Common Integrations - **Prometheus** – for exporting metrics - **Grafana** – for visual dashboards - **CloudWatch / ELK / Zipkin** – for monitoring and tracing