How can I write custom Exceptions?

exception, java

Solution

All you need to do is create a new `class` and have it `extend Exception`.

If you want an `Exception` that is unchecked, you need to `extend RuntimeException`.

Note: A checked `Exception` is one that requires you to either surround the `Exception` in a `try`/`catch` block or have a '`throws`' clause on the method declaration. (like `IOException`) Unchecked `Exceptions` may be thrown just like checked `Exceptions`, but you aren't required to explicitly handle them in any way (`IndexOutOfBoundsException`).

For example:

public class MyNewException extends RuntimeException {

    public MyNewException(){
        super();
    }

    public MyNewException(String message){
        super(message);
    }
}

Problem

How can I create a new `Exception` different from the pre-made types? ``` public class InvalidBankFeeAmountException extends Exception{ public InvalidBankFeeAmountException(String message){ super(message); } } ``` It will show the warning for the InvalidBankFeeAmountException which is written in the first line.

Original source