Question

Need some help on the following problem in java. I have to modify the code I written so far(below) to do the following three things:

a). Write a method called diagnostics that occasionally throws any one of the exceptions you have created depending on the values generated by a random-number generator.

b). Write a method called display that calls diagnostics and provides exception handlers to display a message when an exception occurs. Otherwise, if an exception does not occur, method display should print out "Diagnostic test completed--no problem found."

c). Suppose that the display method contains three catch clauses with parameter types: FootBrakeException, BrakeException, and Exception. Explain which orders of the catch blocks would prevent the execution of an exception handler.

//code

public class AutoExceptions {
   class NoStartException extends Exception {
       public NoStartException() {
           this("No Start Exception");
       }
       public NoStartException(String message) {
           super(message);
       }
           class BadIgnitionException extends NoStartException{
               public BadIgnitionException() {
                   this("Bad Ignition Exception");
               }
               public BadIgnitionException(String message) {
                   super(message);
               }}
           class DeadBatteryException extends NoStartException{
               public DeadBatteryException() {
                   this("Dead Battery Exception");
               }
               public DeadBatteryException(String message) {
                   super(message);
               }
       }
   }
   class LightsException extends Exception {
       public LightsException() {
           this("Lights Exception");
       }
       public LightsException(String message) {
           super(message);
       }
           class HeadLightException extends LightsException{
               public HeadLightException() {
                   this("Head Light Exception");
               }
               public HeadLightException(String message) {
                   super(message);
               }}
           class BrakeLightException extends LightsException{
               public BrakeLightException() {
                   this("Brake Light Exception");
               }
               public BrakeLightException(String message) {
                   super(message);
               }
       }
           class TailLightException extends LightsException{
               public TailLightException() {
                   this("Tail Light Exception");
               }
               public TailLightException(String message) {
                   super(message);
               }
       }
   }
   class BrakeException extends Exception {
       public BrakeException() {
           this("Brake Exception");
       }
       public BrakeException(String message) {
           super(message);
       }
           class FootBrakeException extends BrakeException{
               public FootBrakeException() {
                   this("Foot Brake Exception");
               }
               public FootBrakeException(String message) {
                   super(message);
               }}
           class ParkingBrakeException extends BrakeException{
               public ParkingBrakeException() {
                   this("Parking Brake Exception");
               }
               public ParkingBrakeException(String message) {
                   super(message);
               }
       }
   }
}

Answer 1

Modified Code->

import java.util.Random;

public class AutoExceptions {

    class NoStartException extends Exception {

        public NoStartException() {

            this("No Start Exception");

        }

        public NoStartException(String message) {

            super(message);

        }

        class BadIgnitionException extends NoStartException {

            public BadIgnitionException() {

                this("Bad Ignition Exception");

            }

            public BadIgnitionException(String message) {

                super(message);

            }

        }

        class DeadBatteryException extends NoStartException {

            public DeadBatteryException() {

                this("Dead Battery Exception");

            }

            public DeadBatteryException(String message) {

                super(message);

            }

        }

    }

    class LightsException extends Exception {

        public LightsException() {

            this("Lights Exception");

        }

        public LightsException(String message) {

            super(message);

        }

        class HeadLightException extends LightsException {

            public HeadLightException() {

                this("Head Light Exception");

            }

            public HeadLightException(String message) {

                super(message);

            }

        }

        class BrakeLightException extends LightsException {

            public BrakeLightException() {

                this("Brake Light Exception");

            }

            public BrakeLightException(String message) {

                super(message);

            }

        }

        class TailLightException extends LightsException {

            public TailLightException() {

                this("Tail Light Exception");

            }

            public TailLightException(String message) {

                super(message);

            }

        }

    }

    class BrakeException extends Exception {

        public BrakeException() {

            this("Brake Exception");

        }

        public BrakeException(String message) {

            super(message);

        }

        class FootBrakeException extends BrakeException {

            public FootBrakeException() {

                this("Foot Brake Exception");

            }

            public FootBrakeException(String message) {

                super(message);

            }

        }

        class ParkingBrakeException extends BrakeException {

            public ParkingBrakeException() {

                this("Parking Brake Exception");

            }

            public ParkingBrakeException(String message) {

                super(message);

            }

        }

    }

    void diagnostics() throws Exception{

        Random random=new Random();

        int num = random.nextInt(10000)%5;

        switch(num){

            case 0:

                throw new NoStartException();

            case 1:

                throw new LightsException();

            case 2:

                throw new BrakeException();

            //add more here

        }

    }

    void display(){

        try {

            diagnostics();

            System.out.println("Diagnostic test completed--no problem found.");

        }

        catch (AutoExceptions.BrakeException.FootBrakeException e){

            System.out.println(e.getMessage());

        }

        catch(AutoExceptions.BrakeException e){

            System.out.println(e.getMessage());

        }

        catch (Exception e) {

            System.out.println(e.getMessage());

        }

    }

    public static void main(String[] args) {

        

    }

}

part c)

If footbrakeexception is thrown, first catch blocks will pick it.

If any subclass or self - brakeexcption i thrown, second block will catch it.

else third catch block

ScreenShot

void diagnostics() throws Exception Random random=new Random(); int num = random.nextInt(10080)%5; switch(num) { case 0: throw new NoStartException(); case 1: throw new LightsException(); case 2: throw new BrakeException(); //add more here void display try { diagnostics(); System.out.println("Diagnostic test completed-- no problem found."); catch (AutoExceptions. BrakeException.FootBrakeException e) { System.out.println(e.getMessage); catch(AutoExceptions. BrakeException e) { System.out.println(e.getMessage(); catch (Exception e) { System.out.println(e.getMessage());