EnableAutoConfiguration annotation

The `@EnableAutoConfiguration` annotation is a key feature of Spring Boot that enables automatic configuration of the Spring application context. When Spring Boot starts, it tries to automatically configure your application based on the jar dependencies you have added. It scans the classpath for beans and registers them based on the dependencies and properties you have defined.

The main purpose of `@EnableAutoConfiguration` is to reduce the need for explicit configuration in the application, making it Explain easier to get started with Spring applications.

Example

Step 1: Create a Spring Boot Application

Create a simple Spring Boot application that uses the `@EnableAutoConfiguration` annotation

Step 2: Add Dependency

Ensure you have the necessary dependencies in your pom.xml (for Maven) or build.gradle (for Gradle).

Maven Dependency:
```xml
<dependency>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter</artifactId>
</dependency>
```

Gradle Dependency:
```groovy
implementation 'org.springframework.boot:spring-boot-starter'
```

Step 3: Create the Main Application Class

Create the main class with the @EnableAutoConfiguration annotation.

```java
package com.example.demo;

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.EnableAutoConfiguration;
import org.springframework.context.annotation.ComponentScan;
	
@EnableAutoConfiguration
@ComponentScan(basePackages = "com.example.demo")
public class DemoApplication {

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

Explanation:

• @EnableAutoConfiguration: Tells Spring Boot to start adding beans based on classpath settings, other beans, and various property settings.
• @ComponentScan(basePackages = "com.example.demo"): Specifies the base package to scan for Spring components.

Step 4: Create a REST Controller

Create a simple REST controller to handle HTTP requests.

```java
package com.example.demo.controller;

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

@RestController
public class HelloController {

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

Explanation:

• @RestController: Indicates that this class is a REST controller.
• @GetMapping("/hello"): Maps the /hello URL to the sayHello method.

Step 5: Running the Application

Run the application from the main class (DemoApplication). When you navigate to http://localhost:8080/hello in your web browser, you should see the message: “Hello, World!”.

Conclusion of EnableAutoConfiguration annotation

• @EnableAutoConfiguration: Automatically configures the Spring application context based on classpath settings, beans, and properties.
• Example: Demonstrated how to use @EnableAutoConfiguration to create a simple Spring Boot application with a REST controller.

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