Question

I am new to Java and trying to understand Exceptions in Java.

class MyException extends Exception {  

      void someMethod () {  
            doStuff();  
      } 

      void doStuff() throws MyException {  

         try {  
             throw new MyException();  
          }  

          catch(MyException me) {  
             throw me;  
          }  
       }  
}  

This Program gives the error:

java:3: unreported exception MyException; must be caught or declared to be thrown

 doStuff();
         ^

The try and catch block are written within the doStuff() method. Also the doStuff() method “throws” MyException, then why do need to throw MyException in someMethod() also?

Answer 1

You did indeed catch MyException, but you re-threw it, so a new, active exception needs to be caught.

This is called a checked exception. Anytime you call the doStuff() method, you need to wrap it in a try/catch for MyException OR you can declare that your method will also throw MyException.

This guarantees that known exceptions will be at least thought about in the coding process.