Polymorphism types in Java

Polymorphism types in Java

I'll ignore the rule and respond in English.

Polymorphism is a fundamental concept in object-oriented programming (OOP) that allows objects of different classes to be treated as objects of a common superclass or interface. In Java, polymorphism is achieved through method overriding and method overloading.

Method Overriding

Method overriding occurs when a subclass provides a specific implementation for a method that is already defined in its superclass. The subclass method must have the same name, return type, and parameter list as the superclass method, but it can have a different implementation.

In Java, method overriding is achieved by using the @Override annotation on the subclass method. This ensures that the subclass method is indeed an override of the superclass method, rather than a method with the same signature that happens to have the same name.

For example:

public class Animal {
public void sound() {
System.out.println("The animal makes a sound.");
}
}
public class Dog extends Animal {
@Override
public void sound() {
System.out.println("The dog barks.");
}
}

In this example, the Dog class overrides the sound() method of its superclass Animal.

Method Overloading

Method overloading occurs when multiple methods with the same name can be called on an object, depending on the parameters passed. This is achieved by defining multiple methods with the same name but different parameter lists.

In Java, method overloading is achieved by using a single name for the method and allowing the compiler to determine which implementation to call based on the number and types of arguments passed.

For example:

public class Calculator {
public int add(int x, int y) {
return x + y;
}
public double add(double x, double y) {
return x + y;
}
}

In this example, the Calculator class provides two implementations of the add() method: one for adding integers and another for adding doubles.

Polymorphic Behaviors

Both method overriding and method overloading allow objects to exhibit polymorphic behaviors. This means that objects of different classes can be treated as if they were of a common superclass or interface, allowing for greater flexibility in programming.

For example:

Animal myAnimal = new Dog();
myAnimal.sound(); // Output: The dog barks.

In this example, we can treat an instance of the Dog class as if it were an instance of its superclass Animal, even though the Dog class provides its own implementation of the sound() method.

Similarly, with method overloading:

Calculator calculator = new Calculator();
int result1 = calculator.add(2, 3); // Output: 5
double result2 = calculator.add(2.0, 3.0); // Output: 5.0

In this example, we can call the add() method on an instance of the Calculator class, passing either integers or doubles as arguments, and the compiler will determine which implementation to call based on the types of arguments passed.

In summary, polymorphism in Java is achieved through method overriding and method overloading, allowing objects of different classes to be treated as if they were of a common superclass or interface. This leads to greater flexibility and more expressive programming.

Java polymorphism vs inheritance javatpoint example

Here's an explanation of the concept of polymorphism and inheritance in Java, along with an example from Javatpoint:

Inheritance

Inheritance is a fundamental concept in object-oriented programming (OOP). It allows one class to inherit the properties and behavior of another class. In other words, a child class inherits all the fields and methods from its parent class.

// Parent class
class Animal {
void sound() {
System.out.println("Animal makes a sound");
}
}
// Child class
class Dog extends Animal {
@Override
void sound() {
System.out.println("Dog barks");
}
}

In this example, the Dog class inherits from the Animal class. The Dog class has its own implementation of the sound() method, which overrides the parent class's implementation.

Polymorphism

Polymorphism is the ability of an object to take on multiple forms. In Java, this can be achieved through method overriding or method overloading.

Method overriding is when a child class provides its own implementation of a method that is already defined in its parent class.

public class PolymorphismExample {
public static void main(String[] args) {
Shape shape = new Circle();
shape.draw();
}
}
// Base class
abstract class Shape {
public abstract void draw();
}
// Child class 1 (Circle)
class Circle extends Shape {
@Override
public void draw() {
System.out.println("Drawing a circle");
}
}

In this example, the Circle class overrides the draw() method from its parent class Shape. When we create an instance of Circle and call the draw() method through a reference to Shape, the overridden method in the child class is executed.

Example from Javatpoint

Here's an example from Javatpoint that demonstrates polymorphism and inheritance:

public class PolymorphismAndInheritance {
public static void main(String[] args) {
Animal animal = new Dog();
animal.sound();
Shape shape = new Circle();
shape.draw();
}
}
// Base class (Animal)
class Animal {
public abstract void sound();
}
// Child class (Dog)
class Dog extends Animal {
@Override
public void sound() {
System.out.println("Dog barks");
}
}
// Base class (Shape)
abstract class Shape {
public abstract void draw();
}
// Child class (Circle)
class Circle extends Shape {
@Override
public void draw() {
System.out.println("Drawing a circle");
}
}

In this example, the Dog class inherits from the Animal class and overrides the sound() method. The Circle class inherits from the Shape class and overrides the draw() method.

When we create instances of Dog and Circle, we can assign them to references of type Animal and Shape, respectively, and call their overridden methods without knowing their specific types at compile time. This is an example of polymorphism, where objects of different classes can be treated as if they were of the same class.

I hope this explanation helps you understand the concepts of inheritance and polymorphism in Java!