Spring AOP advice with method rather than @annotation : Why?

Question

I don't understand one thing with the Spring advices. There are two ways which can be used to create an aspect with two advices:

• We can create an empty method with a pointcut annotation. Then, we just have to create methods with an advice which contains the empty method name:

    @Component
    @Aspect
    public class TestAppli{

        private static final Logger LOGGER = LoggerFactory.getLogger(TestAppli.class);

        @Pointcut("@annotation(Loggable)")
        public void executeLogging(){
        }

        @Before("executeLogging()")
        public void method1(JoinPoint joinPoint){
            LOGGER.info("method 1 is called");
        }

        @Before("executeLogging()")
        public void method2(JoinPoint joinPoint){
            LOGGER.info("method 2 is called");
        }
    }

• We can directly create the two methods with @Before("@annotation(Loggable)") without using an empty method and its name. It seems to realise the same operations (it shows text data into the console too):

    @Component
    @Aspect
    public class TestAppli {

        private static final Logger LOGGER = LoggerFactory.getLogger(TestAppli.class);

        @Before("@annotation(Loggable)") 
        public void method1(JoinPoint joinPoint){
            LOGGER.info("method 1 iscalled");
        }

        @Before("@annotation(Loggable)") 
        public void method2(JoinPoint joinPoint){
            LOGGER.info("method 2 is called");
        }   
    }

Please, can you explain me when the second operation must be used? People say it permits something but I don't understand what the thing is.

Answer 1

The basic concepts of Spring AOP can be read here

Advice: Action taken by an aspect at a particular join point

Pointcut: A predicate that matches join points.

With @PointCut annotated method , a pointcut expression to match a join point is declared.

This method name can be then used to associate the pointcut expression with an Advice.

When the pointcut expression is written directly with an advice , it is known as an in-place pointcut expression.

As far as I know , there are no differences when in-place pointcut expressions are used. At the same time the advantage of using @PointCut annotated method is that we can combine several different such methods to have a more readable Advice.

Hope this helps