Arguments Against Annotations

Question

My team is moving to Spring 3.0 and there are some people who want to start moving everything into Annotations. I just get a really bad feeling in my gut (code smell?) when

Answer 1

Like many things, there are pros and cons. In my opinion, some annotations are fine, though sometimes it feels like there is a tendency to overuse annotations when a plain old function calling approach might be superior, and taken as a whole, this can unintentionally increase cognitive load because they increase the number of ways to "do stuff."

Let me explain. For example, I'm glad you mentioned the @Transactional annotation. Most Spring developers probably are going to know about and use @Transactional. But how many of those developers know how @Transactional actually works? And would they know off the top of their head how to create and manage a transaction without using the @Transactional annotation? Using @Transactional makes it easier for me to use transactions in a majority of cases, but in particular cases when I need more fine-grained control over a transaction, it hides those details from me. So in a way it is a double edged sword.

Another example is @Profile in Spring config classes. In the general case, it makes it easier to specify which profiles you want a Spring component loaded in. However, it if you need more powerful logic than just specifying a list of profiles for which you want the component loaded, you would have to get the Environment object yourself and write a function to do this. Again, most Spring developers would probably be familiar with @Profile, but the side effect of that is they become less familiar with the details of how it works, like the Environment.acceptsProfiles(String... profiles) function, for instance.

Finally, when annotations don't work, it can be harder to understand why and you can't just put a breakpoint on the annotation. (For instance, if you forgot the @EnableTransactionManagement on your config, what would happen?) You have to find the annotation processor and debug that. With a function calling approach, you can of course just put a breakpoint in the function.