Igor Venturelli

Posted on Nov 6 • Originally published at igventurelli.io

Getting Started with Java: A Beginner's Guide

#spring #beginners #programming #springboot

Get hands-on with Java! Learn to set up, code your first program, and explore the basics of Spring Boot in this beginner-friendly guide

Java has stood the test of time as one of the most versatile, powerful, and widely-used programming languages. Whether you're just starting your coding journey or looking to add a powerful language to your toolkit, Java is a fantastic choice. It’s not only the backbone of Android development but also plays a crucial role in web, enterprise, and server-side applications. This guide will help you get started with Java, walking you through setting up your environment, writing your first program, and even touching on how Java is used with frameworks like Spring Boot.

Setting Up Your Development Environment

Before we dive into coding, let's set up everything you need to write and run Java code.

Step 1: Install Java Development Kit (JDK)

The JDK is your toolkit for Java programming, providing the compiler, runtime, and necessary libraries. To install:

Visit the Oracle JDK website.
Download the latest version of JDK suitable for your operating system.
Follow the installation instructions.

Step 2: Choose an Integrated Development Environment (IDE)

Java works well in several IDEs, with IntelliJ IDEA, Eclipse, and Visual Studio Code being among the most popular. For beginners, IntelliJ IDEA (Community Edition) offers a user-friendly interface with many helpful features:

Download IntelliJ IDEA from the JetBrains website.
Follow the instructions to install and launch.

Step 3: Verify Installation

Once you’ve installed the JDK and your preferred IDE, open a terminal or command prompt and type:

java -version

If everything was set up correctly, you should see the version number of your JDK displayed.

Writing Your First Java Program

Let's create a simple "Hello, World!" application—a time-honored tradition for beginners. This example will introduce you to the structure of a basic Java program.

Open IntelliJ and create a new project.
In the src folder, create a new Java class named HelloWorld.

Paste in the following code:

public class HelloWorld {
    public static void main(String[] args) {
        System.out.println("Hello, World!");
    }
}

Run the program by right-clicking on the file and selecting “Run HelloWorld.main()”. You should see "Hello, World!" printed in the console.

Java with Spring Boot: A Quick Glance

Java really shines when combined with frameworks, especially for web and enterprise applications. One of the most popular frameworks for building web applications in Java is Spring Boot. It simplifies the setup and development of standalone, production-ready applications.

Let’s expand our "Hello, World!" example to create a simple RESTful API using Spring Boot.

Step 1: Set Up Your Spring Boot Project

Spring Boot provides a web-based tool to generate boilerplate code for your application. Visit start.spring.io and select the following:

Project: Maven Project
Language: Java
Spring Boot Version: (Choose the latest stable version)
Group: com.example
Artifact: hellospring
Dependencies: Add “Spring Web”

Download the generated project and open it in IntelliJ.

Step 2: Write Your First Spring Boot Controller

In your new project, navigate to src/main/java/com/example/hellospring and create a new Java class named HelloController.

Add the following code:

import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;

@RestController
@RequestMapping("/api")
public class HelloController {

    @GetMapping("/hello")
    public String sayHello() {
        return "Hello, World!";
    }
}

This class defines a REST controller with a single endpoint, /api/hello, which returns "Hello, World!" when accessed.

Step 3: Run the Spring Boot Application

In IntelliJ, find the main application file (usually named HellospringApplication.java), and run it. Once running, open a browser and navigate to http://localhost:8080/api/hello. You should see "Hello, World!" displayed.

Key Java Concepts for Beginners

Now that you've created a simple program and seen Java in action with Spring Boot, here are a few foundational concepts to strengthen your understanding:

Variables and Data Types: In Java, every variable has a specific type, such as int, String, or boolean. Knowing data types will help you manage memory efficiently and avoid errors.
Control Structures: Java provides standard control structures like if statements, for loops, and while loops, essential for logic flow in your applications.
Object-Oriented Programming (OOP): Java is fundamentally an OOP language. Concepts like classes, inheritance, and polymorphism are central to Java programming.
Exceptions: Java uses exceptions to handle errors in a controlled way. Learning how to work with try, catch, and finally blocks is essential to write robust programs.

Conclusion

Starting with Java can open doors to a world of opportunities. With strong community support, extensive libraries, and frameworks like Spring Boot, Java remains a powerful language that powers everything from simple web apps to enterprise-grade software. Practice the basics, build small projects, and gradually dive into advanced topics. With dedication, you'll soon be writing efficient, scalable, and well-structured Java applications. Happy coding!

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