Java is Everywhere

Study Java for a better life and future…

1. Polymorphism

Java is an object-oriented language, and polymorphism is one of its features. There are two types of polymorphism in Java. One is compile-time polymorphism and the other is runtime polymorphism.

(1.1) Compile-time Polymorphism

Compile-time polymorphism can be achieved with method overloading and operator overloading. However, Java does not support operator overloading.

(1.1.1) Method Overloading: Multiple functions have the same name but with different parameters. Their parameters can contain different types and various numbers.

Example:

class summation{
    // Method with 2 parameters
    int sum (int a, int b){
        return a+b;
    }
    // Method with the same name but 2 double parameters
    double sum(double a, double b){
        return a+b;
    }
    // Method with the same name but 3 parameters
    int sum(int a, int b, int c){
        return a+b+c;
    }
}

(1.2) Runtime Polymorphism

Runtime Polymorphism or Dynamic Method Dispatch is a process where a function call is resolved at runtime rather than at compile-time. This type of polymorchism is achieved by Method Overriding.

(1.2.1) Method Overriding: In this process of Runtime Polymorphism, an overridden method is called by a reference variable of a superclass.

Example:

class BankAccount{
   void getMoney(){
      System.out.print('Get back the money from your account.');
      return;
   }
}
class TomBankAccount extends BankAccount{
   void getMoney(){
      System.out.print('Tom's Bank Account');
   }
}
class TestPolymorphism{
   public static void main(String[] args){
       BankAccount a;
       BankAccount b;
       a = new BankAccount();
       b = new TomBankAccount();
       a.getMoney();  // runs the method in BankAccount class
       b.getMoney();  // runs the method in TomBankAccount class
   }
}