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How to Use Methods in Java

Updated: Dec 16, 2023

How to Use Methods in Java

Unlocking the Power of Methods in Java: Learn the essential techniques of using methods in Java with our comprehensive guide. Explore step-by-step instructions on how to use methods effectively and efficiently in your Java programs. Java, renowned for its versatility, object-oriented principles, and strong emphasis on code reusability, makes extensive use of methods. In this blog post, we will delve into methods in Java, providing real-world illustrations to help you appreciate their importance and how to use them effectively.

The Role of Methods in Java

In Java, methods are blocks of code encapsulated within classes that perform specific tasks. Methods play several vital roles in Java programming:

  1. Reusability: Methods allow you to define a block of code once and reuse it multiple times throughout your program. This promotes code efficiency and maintainability.

  2. Modularity: Breaking your code into smaller, manageable chunks is made possible by methods. This enhances code organization, readability, and maintainability.

  3. Abstraction: By abstracting the details of their implementation, methods provide clean and straightforward interfaces for other parts of your code. This abstraction hides complexity, making your code more comprehensible.

  4. Encapsulation: You can control access to data by defining methods that manipulate it, which promotes data security and integrity.

Core Java Programming

Java Back-End Development

Anatomy of a Method

Before we explore real-world examples, let's understand the structure of a method in Java: return_type method_name(parameter_list) {

// Method body // Code to perform a specific task return some_value; // (optional) Return statement }

  • return_type: This denotes the data type of the value that the method will return. It can be a primitive type, an object, or void if the method doesn't return anything.

  • method_name: This is the name of the method, following Java's naming conventions (camelCase).

  • parameter_list: A list of input parameters that the method accepts. Parameters are optional and can be of any data type.

  • method body: This is where the code resides that carries out the method's task.

  • return statement (optional): If the method has a return type other than void, it must include a return statement to provide a value of that type.

Now, let's dive into more illustrative real-world examples that transition from good to better use of methods.

Real-World Example: Online Shopping Cart

Imagine you're developing a Java program to simulate an online shopping cart. The program should allow customers to add items to their cart, view the cart, and calculate the total cost. Methods will help encapsulate these actions and improve code organization. Here's a simplified version of such a program:

import java.util.ArrayList;

import java.util.List;

class Product {

String name;

double price;

public Product(String name, double price) { = name;

this.price = price;



class ShoppingCart {

private List<Product> cartItems = new ArrayList<>();

public void addProduct(Product product) {


System.out.println( + " added to the cart.");


public void viewCart() {

System.out.println("Items in your cart:");

for (Product product : cartItems) {

System.out.println( + " - $" + product.price);



public double calculateTotal() {

double total = 0;

for (Product product : cartItems) {

total += product.price;


return total;



public class OnlineShoppingApp {

public static void main(String[] args) {

ShoppingCart cart = new ShoppingCart();

Product laptop = new Product("Laptop", 899.99);

Product headphones = new Product("Headphones", 99.99);




double totalCost = cart.calculateTotal();

System.out.println("Total cost: $" + totalCost);



In this example:

  • The Product class represents products with their name and price.

  • The ShoppingCart class encapsulates the cart functionality with methods to add products, view the cart, and calculate the total cost.

  • The OnlineShoppingApp class demonstrates how these methods can be used to interact with the shopping cart.

This real-world example shows how methods help structure a program related to online shopping, making it organized, modular, and efficient. You can expand upon this concept to create a more robust and feature-rich online shopping application in Java.

Core Java Programming

Java Back-End Development


Methods are the building blocks of Java programming, offering modularity, reusability, and encapsulation. To become a proficient Java developer, it's essential to understand how to create and employ methods effectively.

The transition from good to better methods involves encapsulating complex logic, enhancing code organization, and making your code more efficient. As you continue your journey in Java programming, remember that methods are not just about executing code; they are about structuring code to be readable, maintainable, and efficient.

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