Exception filenotfoundexception is never thrown in body of corresponding try statement

Question

Problem :

I am facing a problem with the exception handling in Java, following is my code. I am facing compiler error when I try to execute my code. The error is as below:

exception MojException is never thrown in body of corresponding try statement

Below is my code:

public class MyTest { 

public static void main(String[] args) throws MyMojException {

// TODO Auto-generated method stub

for(int m=1;m<args.length;m++){

try{

    Integer.parseInt(args[m-1]);

   }

  catch(MyMojException e){

  throw new MyMojException("The Bledne dane");

  }

 try{

WierszTrojkataPascala w = new WierszTrojkataPascala(Integer.parseInt(args[0]));

System.out.println(args[m]+" : "+w.wspolczynnik(Integer.parseInt(args[m])));

 }

 catch(MojException e){

 throw new MojException(args[m]+" "+e.getMessage());

      }

    }

  }

}

And here is the code for MyMojException:

public class MyMojException extends Exception{

    MyMojException(String str){

        super(str);

    }

}

Can anyone suggest solution on my issue?

Answer 1

The catch-block in your try statement needs to catch exactly the exception that the code inside your try {}-block can throw or the super class of that as below

try {

//do something that throws ExceptionA, e.g.

throw new ExceptionA("I am the Exception Alpha!");

}

catch(ExceptionA e) {

//do something to handle the exception, e.g.

System.out.println("Message: " + e.getMessage());

}

But what you are trying to do is as following :

try {

throw new ExceptionB("I am the Exception Bravo!");

}

catch(ExceptionA e) {

System.out.println("Message: " + e.getMessage());

}

This will definitely lead to the compiler error, as java knows that you are trying to catch an exception that will never be thrown. So you will get: exception ExceptionA is never thrown in body of corresponding try statement.