Skip to main content

Java Exception Handling MCQ Test

  Loading…
Post a Comment

The @Override annotation

The `@Override` annotation is used in Java to indicate that a method in a subclass is overriding a method with the same signature in its superclass. It is not mandatory to use `@Override`, but it helps in detecting errors during compilation if the method signature does not match any method in the superclass.


Here are some key points about `@Override`:


1. Purpose: It provides compile-time checking that a method is indeed overriding a method from a superclass. If there is a mismatch in the method signature (e.g., misspelling of method name, incorrect parameters), the compiler will generate an error.


2. Usage: `@Override` is placed immediately before the method declaration in the subclass that is intended to override a method in the superclass.


3. Compatibility: `@Override` annotation was introduced in Java 5. It can only be used with methods that are overriding a superclass method. If a method is not overriding a superclass method, using `@Override` will result in a compilation error.


4. Benefits: Helps in code maintenance and readability by clearly indicating that a method is intended to override a method from the superclass. It also ensures that the method signature is correct.


Here's an example demonstrating the usage of `@Override`:



class Animal {

    void makeSound() {

        System.out.println("Animal makes a sound");

    }

}


class Dog extends Animal {

    @Override

    void makeSound() { // Overriding the makeSound method from the superclass

        System.out.println("Dog barks");

    }

}


public class Main {

    public static void main(String[] args) {

        Animal animal = new Dog(); // Creating an instance of Dog but referenced as Animal

        animal.makeSound(); // Calls the makeSound method of Dog class

    }

}


In this example, the `makeSound()` method in the `Dog` class overrides the `makeSound()` method in the `Animal` class. The `@Override` annotation is used to explicitly indicate that the method is intended to override a method from the superclass. If there is a mistake in the method signature, such as misspelling `makeSound` as `makeSounds`, the compiler will generate an error, helping to catch errors early in the development process.

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