Embedded server concept in Spring Boot - Mini Project: Build & Apply

Embedded Server Concept in Spring Boot

📖 Scenario: You are building a simple Spring Boot web application that runs with an embedded server. This means the server is included inside your application, so you don't need to install or configure a separate web server.This setup is common for microservices and makes deployment easier.

🎯 Goal: Create a basic Spring Boot application with an embedded Tomcat server that starts automatically and serves a simple web page.

📋 What You'll Learn

Create a Spring Boot application class with the @SpringBootApplication annotation

Add a configuration property to set the server port to 8081

Create a REST controller with a GET endpoint /hello that returns a welcome message

Ensure the application runs with the embedded server on port 8081

💡 Why This Matters

🌍 Real World

Embedded servers allow developers to package web applications with their own server, simplifying deployment and making applications portable.

💼 Career

Understanding embedded servers is essential for modern Java backend development, especially in microservices and cloud-native applications.

1

Create the Spring Boot application class

Create a class called EmbeddedServerApplication in package com.example.demo. Annotate it with @SpringBootApplication and add the main method that runs SpringApplication.run(EmbeddedServerApplication.class, args).

Spring Boot

package com.example.demo;

// Your code here

Need a hint?

Use @SpringBootApplication on the class and add a main method that calls SpringApplication.run.

2

Configure the embedded server port

Create a file named application.properties in src/main/resources. Add the line server.port=8081 to set the embedded server port to 8081.

Spring Boot

package com.example.demo;

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;

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

# Create src/main/resources/application.properties
# Add server.port=8081 inside it

Need a hint?

The embedded server port is set in application.properties with server.port=8081.

3

Create a REST controller with a GET endpoint

Create a class called HelloController in package com.example.demo. Annotate it with @RestController. Add a method sayHello annotated with @GetMapping("/hello") that returns the string "Welcome to the embedded server!".

Spring Boot

package com.example.demo;

// Your code here to create HelloController with @RestController and @GetMapping("/hello")

Need a hint?

Use @RestController on the class and @GetMapping("/hello") on the method that returns the welcome string.

4

Run the application with embedded server

Ensure the application class EmbeddedServerApplication has the main method that runs the Spring Boot application. This will start the embedded Tomcat server on port 8081 automatically.

Spring Boot

package com.example.demo;

// Confirm main method runs SpringApplication.run

// Your code here

Need a hint?

The main method must call SpringApplication.run to start the embedded server.