Exception Handler

 To make method mark with @ExceptionHandler

Accepts parameters to help with the exception handling and provide response.

Sample Exception handler 

- use the annotation

- pass the exception that this exception hanlder function handles as an argument

- below is handled for indexoutofboundexception

If we add this in controller: Then this will become global exception for that controller class

Can add @ResponseStatus to return desired HTTP Error code

Now when Controller gets this exception, it also return "Oops, something went wrong@ along with HTTP Error Code 400 as provided with @ResponseStatus above

Topic 3:

Controller can have multiple exception handler to handle different exceptions.

One is to add all exceptions as below, which is not practically possible in many cases

OR make indepeent handler so that we can customize the error code 

and by adding below to cover all other unhandled exceptions.

Topic  4)

To  embed some content from request recived  in response while handling exceptions, we can use HttpServletRequet  and Exception e value can be used to log to know about the exception

FAQ :

Q) Can I use ExceptionHandler annotation in any class?

Ans:

The @ExceptionHandler annotation is used in Spring Framework to define a method that handles exceptions thrown by a controller method.

In order to use the @ExceptionHandler annotation, the method that handles the exception should be defined within a class annotated with @ControllerAdvice or @RestControllerAdvice. These annotations allow the class to handle exceptions across multiple controller classes.

So, the answer is no, you cannot use the @ExceptionHandler annotation in any class. It should only be used within a class annotated with @ControllerAdvice or @RestControllerAdvice.