Spring AOP works without @EnableAspectJAutoProxy?

Question

I am learning Spring (currently its AOP framework). Even though all sources I\'ve read say that to enable AOP one needs to use @EnableAspectJAutoProxy annotatio

Answer 1

The @SpringBootApplication annotation contains the @EnableAutoConfiguration annotation. This autoconfiguration is one of the attractions of Spring Boot and makes configuration simpler. The auto configuration uses @Conditional type annotations (like @ConditionalOnClass and @ConditionalOnProperty) to scan the classpath and look for key classes that trigger the loading of 'modules' like AOP.

Here is an example AopAutoConfiguration.java

import org.aspectj.lang.annotation.Aspect;
import org.aspectj.lang.reflect.Advice;
import org.aspectj.weaver.AnnotatedElement;

@Configuration
@ConditionalOnClass({ EnableAspectJAutoProxy.class, Aspect.class, Advice.class,
    AnnotatedElement.class })
@ConditionalOnProperty(prefix = "spring.aop", name = "auto", havingValue = "true", matchIfMissing = true)
public class AopAutoConfiguration {

  @Configuration
  @EnableAspectJAutoProxy(proxyTargetClass = false)
  @ConditionalOnProperty(prefix = "spring.aop", name = "proxy-target-class", havingValue = "false", matchIfMissing = false)
  public static class JdkDynamicAutoProxyConfiguration {

  }

  @Configuration
  @EnableAspectJAutoProxy(proxyTargetClass = true)
  @ConditionalOnProperty(prefix = "spring.aop", name = "proxy-target-class", havingValue = "true", matchIfMissing = true)
  public static class CglibAutoProxyConfiguration {

  }

}

As you can see, if you add one of the above aop classes to your class path (or property), Spring will detect it and effectively behave as if you had the @EnableAspectJAutoProxy annotation on your main class.

Your project has a file LoggerHogger which has an @Aspect.