Java

Methods
Methods is a block of code
Methods is used for code reusability
Methods are used to perform certain actions, and they are also known as functions

Why methods? ---> To Reduce the code

HOW TO DEFINED A METHOD?

class Calc{
public static void main (String[] args){
Calc casio = new Calc(); ----->object creation
casio.add()  ------> method calling
public void add(){    ---------> method define
int i=10;
int j=20;
int res=i+j;
System.out.println(res)  -------> method define
}
}
}

output:
30

METHOD OVERLOADING
Same method name but different type of arguments / different number of arguments is called method overloading

class Calc{
public static void main (String[] args){
Calc casio = new Calc(); ----->object creation
casio.add(10,20);  ------> method calling
casio.add(10,20,30);  
public void add(int i,intj){    ---------> method define
int res=i+j;
System.out.println(res)  -------> method define
}
public void add(int i,intj,intk){    ---------> method define
int res=i+j+k;
System.out.println(res)  -------> method define
}
}
}

output:
30
60

Return type
Void ---> void does not return any value

public void add(){
---
---
}

In Java System.out.println() ---> is also a method overloading

System.out.println(10);
System.out.println();
System.out.println(10.0);
System.out.println(True);
System.out.println("abc");

Because it contain same method name but different type of argument

Polymorphism
Method overloading is also called as compile-time polymorphism
Method overriding is also called as run-time polymorphism