Bootstrap Example

@EnableAutoConfiguration Spring Boot Example

Author: Sai K

In this article, we will discuss the importance of the annotation @EnableAutoConfiguration with an example

@EnableAutoConfiguration Annotation Overview

@EnableAutoConfiguration annotation tells Spring Boot to “guess” how you want to configure Spring, based on the jar dependencies that you have added.

Since the spring-boot-starter-web dependency added to classpath leads to configuring Tomcat and Spring MVC, the auto-configuration assumes that you are developing a web application and sets up Spring accordingly.

<dependency>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-web</artifactId>
</dependency>

When using @SpringBootApplication annotation, the auto-configuration of the context is automatically enabled, and adding this annotation has, therefore, no additional effect.

The below diagram shows the internal implementation of @EnableAutoConfiguration :

@EnableAutoConfiguration Annotation Example

Let's add @EnableAutoConfiguration annotation to the Application class or Main class to enable an auto-configuration feature in the Spring boot project.

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

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

@EnableAutoConfiguration Annotation Optional Elements

Class< ?>[] exclude - Exclude specific auto-configuration classes such that they will never be applied.
String[] excludeName - Exclude specific auto-configuration class names such that they will never be applied.

Disabling Specific Auto-configuration Classes

If you find that specific auto-configuration classes that you do not want are being applied, you can use the exclude attribute of @EnableAutoConfiguration to disable them, as shown in the following example:

import org.springframework.boot.autoconfigure.*;
import org.springframework.boot.autoconfigure.jdbc.*;
import org.springframework.context.annotation.*;

@Configuration
@EnableAutoConfiguration(exclude={DataSourceAutoConfiguration.class})
public class MyConfiguration {
}

We can use the excludeName attribute of the annotation and specify the fully qualified name instead.

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

@EnableAutoConfiguration(excludeName = {"org.springframework.boot.autoconfigure.thymeleaf.ThymeleafAutoConfiguration",
"org.springframework.boot.autoconfigure.jdbc.DataSourceAutoConfiguration"})
public class Application {
    public static void main(String[] args) {
        SpringApplication.run(Application.class, args);
    }
}

Spring Boot Toturial

Related Spring and Spring Boot Annotations

Spring Boot @Bean Annotation Example
Spring @Qualifier Annotation Example
Spring @Autowired Annotation with Example
Spring @Bean Annotation with Example
Spring @Configuration Annotation with Example
Spring @PropertySource Annotation with Example
Spring @Import Annotation with Example
Spring @ImportResource Annotation Example
Spring - @Lazy Annotation Example
Spring - @Primary Annotation Example
Spring @PostConstruct and @PreDestroy Example
Spring @Repository Annotation
Spring @Service Annotation
The Spring @Controller and @RestController Annotations
Spring Boot @Component, @Controller, @Repository and @Service
Spring @Scope annotation with Prototype Scope Example
Spring @Scope annotation with Singleton Scope Example
Spring Boot @PathVariable
Spring Boot @ResponseBody
Spring @RequestBody - Binding Method Parameters to Request Body
Spring Boot @ResponseStatus Annotation
Spring Boot - Creating Asynchronous Methods using @Async Annotation
@SpringBootTest Spring Boot Example
@SpringBootTest vs @WebMvcTest
@DataJpaTest Spring Boot Example
Spring @PostConstruct and @PreDestroy Example
Spring @GetMapping, @PostMapping, @PutMapping, @DeleteMapping and @PatchMapping
Spring Boot @EnableAutoConfiguration Annotation with Example
Spring Boot @SpringBootApplication Annotation with Example