Question

In-Class coding exercise: (try - catch) (pass / fail)

The purpose of this in-class coding exercise is to simulate various exception conditions using the program provided.

package com.InClass;
/*
* This program demonstrates the ability of catching different types of exceptions"
* You will have to modify the method() codes to trigger various/different exceptions.
* inClass Coding ( you will have to remove (comment out) the previous error condition before moving to trigger the next)
* 1) throw a myExcept exception (this is defined with an extends to Exception (see code)
* 2) use method () to trip a Arithmetic exception
* 3) use method () to trip a nullPointException
* 4) use method () call to trip a runtime exception
* 5) inside the myExcept error to inject an arithmetic error and watch it behave differently from step1 22
*
*/
public class TestExceptions {
   public static void main(String[] args) {
       try {
           // throw myException() first.
  
             
            method();
            System.out.println(" after the method call");
       }
       catch (MyExcept ex){
           System.out.println(" MyExcept error");
             
       }
       catch (ArithmeticException ex){
           System.out.println(" ArithmeticEx error");
             
       }
       catch (NullPointerException ex) {
           System.out.println(" nullPointException !!! ");
       }
       catch (IndexOutOfBoundsException e) {
           System.out.println(" index out of bounds...");
       }
       catch (RuntimeException ex ) {
           System.out.println(" Runtime exception");
           System.out.println(ex.getMessage());
             
       }
       catch (Exception e ) {
           System.out.println(" Exception");     
       }

       finally {
       System.out.println(" finally After the catch");
       }
   }
     
   static void method() throws Exception {

// create ArithmeticException
         
         
         
// create RuntimeExceptiom         
         

         
         
// create a null point exception here -- fix the exception above first

         
         
         
// create a ClassCastException here which is NOT on catch "watch" listed above

//   throw new Exception(); // trigger an Exceptiom
   }
}
class MyExcept extends Exception { // creating your custome error
   MyExcept(){
//       int y = 1/0; // uncomment this line to introduce an aritmetic exception inside your MyExcept
   System.out.println(" inside my custome MyExcept");
   }

}

Please complete the missing exceptions. Ignore the spellings mistakes/grammer, it's how the professor writes.

Instructions might be a bit hard to follow so please bear that in mind. Complete as much as possible.

Thank you.

Answer 1

I have implemented all the comments in the method() function and also provided comments so that you can follow.

You need to run the program several times running each exception at a time while commenting the rest. Hope this helps you, let me know for any questions or in case you have any follow up question.

Thanks : )

========================================================================

public class TestExceptions {

    public static void main(String[] args) {
        try {
            // when you want to run the below line please comment the next two lines
            // i.e comment method() and System.out.println(" after the method call");
            throw new MyExcept();

            // when you want to run the below 2 lines comment the above line i.e throw new MyExcept();
            //method();
            //System.out.println(" after the method call");

        } catch (MyExcept ex) {
            System.out.println(" MyExcept error");

        } catch (ArithmeticException ex) {
            System.out.println(" ArithmeticEx error");

        } catch (NullPointerException ex) {
            System.out.println(" nullPointException !!! ");
        } catch (IndexOutOfBoundsException e) {
            System.out.println(" index out of bounds...");
        } catch (RuntimeException ex) {
            System.out.println(" Runtime exception");
            System.out.println(ex.getMessage());

        } catch (Exception e) {
            System.out.println(" Exception");
        } finally {
            System.out.println(" finally After the catch");
        }
    }

    static void method() throws Exception {

        // create ArithmeticException
        // try to divide by zero; this will result in an Arithmetic Exception;
        int result = 5 / 0; // divide by zero will lead to an  Arithmetic Exception;

        // create RuntimeException;
        // we can create an empty string and access the 5th character;
        String empty = "";
        System.out.println("Try to print the 5th character: " + empty.charAt(4));


        // create a null point exception here -- fix the exception above first
        // Create an array pointing to null and then try to access the 1st element
        int[] nullArray = null;
        System.out.println("1st element value: " + nullArray[0]);

        // create a ClassCastException here which is NOT on catch "watch" listed above
        Object s = new String();
        Integer i = (Integer) s; // trying to cast a String to Integer class this will lead to ClassCastException

        //   throw new Exception(); // trigger an Exceptiom
        throw new Exception("Exception");
    }
}

class MyExcept extends Exception { // creating your custome error

    public MyExcept() {
      int y = 1/0; // uncomment this line to introduce an aritmetic exception inside your MyExcept
        System.out.println("Inside my custom MyExcept");
    }

}

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