Skip to main content

Java Exception Handling MCQ Test

  Loading…
Post a Comment

Custom Exceptions

In Java, you can create custom exceptions by extending the `Exception` class or one of its subclasses like `RuntimeException`. Custom exceptions are useful when you want to define your own exception types to represent specific error conditions in your application.

Syntax for creating a custom exception:

public class CustomException extends Exception {

    // Constructors, methods, and additional members can be defined here

}



Example of a custom exception:

public class InvalidAgeException extends Exception {

    public InvalidAgeException(String message) {

        super(message);

    }

}


public class AgeValidator {

    public static void validateAge(int age) throws InvalidAgeException {

        if (age < 0) {

            throw new InvalidAgeException("Age cannot be negative");

        }

        if (age < 18) {

            throw new InvalidAgeException("Must be at least 18 years old");

        }

        System.out.println("Age is valid");

    }


    public static void main(String[] args) {

        try {

            validateAge(20);

            validateAge(-5); // This will throw an InvalidAgeException

        } catch (InvalidAgeException e) {

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

        }

    }

}



In this example:

- We create a custom exception `InvalidAgeException` by extending the `Exception` class and providing a constructor to set the error message.

- The `validateAge` method throws `InvalidAgeException` if the age is negative or less than 18.

- In the `main` method, we catch `InvalidAgeException` and handle it appropriately.


Analogy:


Think of a custom exception as a specialized tool or equipment designed for a specific task. For example, in a carpentry workshop, if you encounter a particular type of material that requires a unique cutting technique, you might design a custom saw blade specifically for that material. Similarly, in Java, custom exceptions allow you to create specialized error-handling mechanisms tailored to specific error conditions in your application.

Labels:

Comments

Post a Comment

Popular posts from this blog

Passing and Returning Objects in Java Methods

Passing and Returning Objects in Java Methods In Java, objects can be passed as parameters to methods and returned from methods just like other primitive data types. This allows for flexibility and the manipulation of object state within methods. Let's explore how passing and returning objects work in Java. Passing Objects as Parameters When you pass an object as a parameter to a method, you are essentially passing a reference to that object. This means that changes made to the object inside the method will affect the original object outside the method.  Example: class Car {     String model;     Car(String model) {         this.model = model;     } } public class CarProcessor {     // Method to modify the Car object     static void modifyCar(Car car, String newModel) {         car.model = newModel;     }     public static void main(String[] args) {       ...
Post a Comment
Read more

Chained Exceptions

 Chained exceptions, also known as nested exceptions, allow you to associate one exception with another. This feature is useful when you want to provide more context or information about the cause of an exception. In Java, you can chain exceptions using constructors that take a `Throwable` (or its subclasses) as an argument. Syntax: try {     // Code that may throw an exception } catch (ExceptionType1 e1) {     throw new ExceptionType2("Additional information", e1); } Explanation: - Inside a `catch` block, you can create a new exception object and pass the original exception (`e1`) as the cause. - The chained exception (`ExceptionType2`) includes a message and the original exception (`e1`) as its cause. - This technique allows you to preserve the original exception's stack trace and context while providing additional information about the higher-level exception. - Chained exceptions can be caught and processed at higher levels of the call stack, allowing for bet...
Post a Comment
Read more