Polymorphism in Java

Back to Java for DSA
Arjit Sharma
01 Min

Polymorphism is same thing behaving differently depending on the context.

In Java, this shows up in two main ways: Compile-time and Run-time.

Compile time Polymorphism ( Static Binding )

Can be achieved using method overloading. The compiler determines which method to invoke based on the method signature.

class Example{

    int sum(int a, int b) {
	    return a+b;
    }
		
	  int sum(int a, int b, int c) {
	    return a+b+c;
    }

	  public static void main(String[] args) {
        Example obj = new Example();
				obj.sum(2,5);
				obj.sum(1,2,3);
    }
}

Run time (Dynamic Binding )

Can be achieved using method overriding. This occurs when a subclass provides a specific implementation of a method that is already defined in its superclass. The method that gets called is determined at runtime, based on the object’s type.

class Animal {
    void sound() {
        System.out.println("Animal makes a sound");
    }
}

class Dog extends Animal {
    // Overriding the sound() method
    @Override
    void sound() {
        System.out.println("Dog barks");
    }
}


public class Example{
    public static void main(String[] args) {
        Animal obj;
        // obj reference points to a Dog object
        obj = new Dog();
        obj.sound();  // Outputs: Dog barks
    }
}
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