OOP Polymorphism

Polymorphism

• the concept of entity providing multiple implementations or behaviors

• ability of a variable to change behavior according to what object instance is holding.

• This allows multiple objects of different subclasses to be treated as objects as a single parent class

Compile-Time Or Static Polymorphism

• refers to behaviour that is resolved when your Java

class is compiled.

• Method overloading is using method of same name to do different things based on the parameters passed.

• Illustration — Method Overloading

• return

• new

class MultiplyFun {

int multiply(int a, int b) {

r____ a * b;

}

int multiply(int a, int b, int c) {

return (a * b) + c;

}

}

public class Main {

public static void main(String[] args) {

MultiplyFun mf = __ MultiplyFun();

System.out.println(mf.multiply(2, 4));

System.out.println(mf.multiply(2, 7, 3));

}

}

• Illustration — Method Overloading

• void overloading

• obj

class OperatorOVERDDN {

v__ o____(String str1, String str2) {

String s = str1 + str2;

System.out.println("Concatenated String = " + s);

}

void operator(int a, int b) {

int c = a + b;

System.out.println("Sum = " + c);

}

}

class Main {

public static void main(String[] args) {

OperatorOVERDDN __= new OperatorOVERDDN();

obj.operator(2, 3);

obj.operator("joe", "now");

}

}

Run-Time Or Dynamic Polymorphism

• Definition: Resolved when your Java class is run by the JVM.

• Key Mechanism: Method overriding by a subclass is an example of run-time polymorphism.

Method Overriding Explained

• Child classes provide their own implementation of a method already defined in the parent class.

• The JVM determines which version of the method to execute—parent or child—based on the object used to invoke the method.

class Parent {

void print() {

System.out.println("Parent");

}

}

class SubClass1 extends Parent {

void print() {

System.out.println("SubClass 1");

}

}

class SubClass2 extends Parent {

void print() {

System.out.println("SubClass 2");

}

}

public class TestPolymorphism3 {

public static void main(String[] args) {

Parent a;

a = new SubClass1();

a.print(); 

a = new SubClass2();

a.print();

}

}

Overriding vs Overloading

advantage of polymorphism