Maintainability of Java annotations?

Question

My project is slowly implementing Java annotations. Half of the developers - myself included - find that doing anything complex with annotations seems to add to our overall maintenance burden. The other half of the team thinks they're the bee's knees.

What's your real-world experience with teams of developers being able to maintain annotated code?

Answer 1

My personal experience is that, on average, dealing with annotations is far easier for most developers than dealing with your standard Java XML Configuration hell. For things like JPA and Spring testing they are absolute life-savers.

The good thing about annotations is that they make configuration on your classes self-documenting. Now, instead of having to search through a huge XML file to try and figure out how a framework is using your class, your class tells you.

Usually the issue with changes like this is that getting used to them simply takes time. Most people, including developers, resist change. I remember when I started working with Spring. For the first few weeks I wondered why anyone would put up with the headaches associated with it. Then, a few weeks later, I wondered how I'd ever lived without it.

Answer 2

I feel it breaks into two uses of annotations - annotations to provide a 'description' of a class vs. annotations to provide a 'dependency' of the class.

I'm fine with a 'description' use of annotations on the class - that's something that belongs on the class and the annotation helps to make a shorthand version of that - JPA annotations fall under this.

However, I don't really like the 'dependency' annotations - if you're putting the dependency directly on the class - even if it's determined at runtime from an annotation rather than at compile time in the class - isn't that breaking dependency injection? (perhaps in spirit rather than in rule...)

It may be personal preference, but I like the one big XML file that contains all the dependency information of my application - I view this as 'application configuration' rather than 'class configuration'. I'd rather search through the one known location than searching through all the classes in the app.