spring-boot

Spring Boot 3.x - Production-Ready Java Framework

Overview

Spring Boot is an opinionated Java framework for building production-ready applications with minimal configuration. It provides auto-configuration, embedded servers, and production-ready features like health checks and metrics.

Key Features:

• Auto-configuration (sensible defaults)
• Embedded servers (Tomcat, Jetty, Undertow)
• Dependency Injection with @Autowired
• Spring Data JPA for database access
• Spring Security for authentication/authorization
• Actuator for production monitoring
• Built-in testing support

Requirements:

• Java 17+ (Spring Boot 3.x requires Java 17 minimum)
• Maven or Gradle

Quick Start:

# Create project from Spring Initializr
curl https://start.spring.io/starter.zip \
  -d type=maven-project \
  -d language=java \
  -d bootVersion=3.2.0 \
  -d dependencies=web,data-jpa,postgresql,lombok,actuator \
  -d name=myapp \
  -o myapp.zip && unzip myapp.zip

# Run the application
cd myapp
./mvnw spring-boot:run

Project Structure

src/
├── main/
│   ├── java/com/example/myapp/
│   │   ├── MyappApplication.java      # Main class
│   │   ├── config/                    # @Configuration classes
│   │   ├── controller/                # @RestController classes
│   │   ├── service/                   # @Service classes
│   │   ├── repository/                # @Repository interfaces
│   │   ├── model/                     # Entity classes
│   │   ├── dto/                       # Data Transfer Objects
│   │   └── exception/                 # Exception handlers
│   └── resources/
│       ├── application.yml            # Configuration
│       └── application-{profile}.yml  # Profile-specific config
└── test/
    └── java/com/example/myapp/        # Test classes

Core Annotations

Application Setup

// Main application class
@SpringBootApplication  // Combines @Configuration, @EnableAutoConfiguration, @ComponentScan
public class MyappApplication {
    public static void main(String[] args) {
        SpringApplication.run(MyappApplication.class, args);
    }
}