How can I write custom Exceptions?

Question

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.

Answer 1

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);     } } 

Answer 2

just extend either

• Exception, if you want your exception to be checked (i.e: required in a throws clause)
• RuntimeException, if you want your exception to be unchecked.