Spring Boot - First Application

Spring Boot simplifies the process of building production-ready applications with the Spring Framework. In this guide, we’ll walk through creating your first Spring Boot application step by step.

🌟 Prerequisites

📋 Before starting, ensure you have the following:

☕ Java Development Kit (JDK) 17+ installed
📦 Maven or Gradle installed
🖥️ A Java IDE (e.g., IntelliJ IDEA, Eclipse, or Visual Studio Code)

🛠️ Step 1: Create a Spring Boot Project

You can create your first Spring Boot project in two ways:

Using Spring Initializr 🖱️

Visit Spring Initializr.
Configure the following:
- 📂 Project: Maven
- 👨‍💻 Language: Java or Kotlin
- 🔄 Spring Boot Version: 3.0.0 (or the latest version).
- 📜 Add dependencies: Spring Web
Click Generate to download the project files.

Using IntelliJ IDEA 💻

Open IntelliJ IDEA.
Go to New Project > Spring Initializr.
Configure similar parameters as mentioned above.

📖 Step 2: Writing Your First Endpoint

Let’s write a simple endpoint to say hello:

package com.example.demo;

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RestController;

@SpringBootApplication
@RestController
public class DemoApplication {
    public static void main(String[] args) {
        SpringApplication.run(DemoApplication.class, args);
    }

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

package com.example.demo

import org.springframework.boot.autoconfigure.SpringBootApplication
import org.springframework.boot.runApplication
import org.springframework.web.bind.annotation.GetMapping
import org.springframework.web.bind.annotation.RestController

@SpringBootApplication
@RestController
class DemoApplication

fun main(args: Array<String>) {
    runApplication<DemoApplication>(*args)
}

@GetMapping("/hello")
fun sayHello(): String {
    return "Hello, Spring Boot!"
}

▶️ Step 3: Run the Application

Open a terminal in the project folder.
Execute the command to run your application:

./mvnw spring-boot:run

Access the endpoint at:
```
http://localhost:8080/hello
```

Response:

Hello, Spring Boot!

This post covers the basics of creating a Spring Boot project, writing an endpoint, and running it successfully.