Methods in Java

Methods
A method is a block of code which only runs when it is called.You can pass data, known as parameters, into a method.Methods are used to perform certain actions, and they are also known as functions.
Why use methods? To reuse code: define the code once, and use it many times.
Create a Method
A method must be declared within a class. It is defined with the name of the method, followed by parentheses (). Java provides some pre-defined methods, such as System.out.println(), but you can also create your own methods to perform certain actions.

//Create a method inside Main://

public class Geeks
{
    // An example method
    public void printMessage() {
        System.out.println("Hello, Geeks!");
    }

    public static void main(String[] args) {

        // Create an instance of the class
        // containing the method
        Geeks obj = new Geeks();

        // Calling the method
        obj.printMessage(); 
    }
}
O/P:
Hello, Geeks!

Syntax of Java Methods

returnType methodName(parameters) {
  // method body
 return value; // optional (only if returnType is not void)
}

Method Overloading
Same method name with different number of arguments or with diiferent type of arguments are called method overloading or compile time polymorphism.

public class Supermarket
{
//fields
static String supermarketname="D-Mart";
static int supermarketdoorno=13/1;
//non-static variables
String things;
int price;
int discount;
public Supermarket(String things,int price){
this.things=things;
this.price=price;
}
public Supermarket(String things,int price,int discount){
this.things=things;
this.price=price;
this.discount=discount;
}
public static void main(String[] args)
{
//object
Supermarket things1=new Supermarket("Rosemilk",30);
Supermarket things2=new Supermarket("Galaxychocky",50);
Supermarket things3=new Supermarket("Kinderjoy",50,20);
things1.buy();
things1.buy(10);
 System.out.println(Supermarket.supermarketname);
 System.out.println(Supermarket.supermarketdoorno);
 System.out.println(things1.things);
 System.out.println("₹" + things1.price);
 System.out.println(things2.things);
 System.out.println("₹" + things2.price);
 System.out.println(things3.things);
 System.out.println("₹" + things3.price);
  System.out.println(things3.discount + "%" );
 }
 //method overloading
 public void buy(){
 System.out.println("buy-method");
 }
 public void buy(int account){
 System.out.println("buy-method-one-argument");
 }
}
o/p:
buy-method
buy-method-one-argument
D-Mart
13
Rosemilk
₹30
Galaxychocky
₹50
Kinderjoy
₹50
20%

References
https://www.w3schools.com/java/java_methods.asp
https://www.geeksforgeeks.org/java/methods-in-java/