Question

For homework, I have to develop an exceptions code:

“Use inheritance to create a superclass of exception called ExceptionA, and two subclasses of the exception called ExceptionB and ExceptionC, where ExceptionB extends ExceptionA, and ExceptionC extends ExceptionB. Develop a program to prove that the catch block for the type ExceptionA catches exceptions of ExceptionB and ExceptionC“.

I do not understand how to do this.

Answer 1

Here is a very simple code. You can further enhance for your learning.

Create exception ExceptionA and define require constructors and methods:

    public class ExceptionA extends Exception {

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

Create exception ExceptionB and define require constructors and methods:

    public class ExceptionB extends ExceptionA {

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

Create exception ExceptionC and define require constructors and methods:

    public class ExceptionC extends ExceptionB {

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

Create TestException class which catches ExceptionB and ExceptionC using ExceptionA as below:

    public class TestException {

        public static void main(String[] args){

            try{
                getExceptionB();
            }catch(ExceptionA ea){
                ea.printStackTrace();
            }

            try{
                getExceptionC();
            }catch(ExceptionA ea){
                ea.printStackTrace();
            }

        }

        public static void  getExceptionB() throws ExceptionB{
            throw new ExceptionB("Exception B");
        }

        public static void  getExceptionC() throws ExceptionC{
            throw new ExceptionC("Exception C");
        }

    }