[mrbrowning]

I grew to really hate annotation-based magic when I worked on a project that used Jackson for JSON serialization. Not only does it circumvent the type system entirely, it also makes errors incredibly hard to track down by virtue of the fact that there are next to no static constraints on how annotations are used. Something as simple as adding a serializable field to an interface or object often ended up requiring a ridiculous amount of trial and error to get right. I think annotations are valuable if used judiciously, but unfettered annotation-based metaprogramming only ever leads to pain in my experience.

[raducu]

Java is not the most powerful language, yet it has huge adoption; the main reason is the number of quite OK and very powerful libraries.

Sure, it's very easy to add Jackson, but people severly underestimate the problem of JSON <-> POJO mapping(multiple ways of doing it and different programmers wanting to do it in different ways). So when you start it's very easy to just add some Jackson annotations and you think it's going to be smooth sailing from now on; add some complexity down the road and you just use some stackoverflow recipes to do the thing I want (without any in-depth Jackson knowledge) and it still is ok-ish; add some more complexity down the road and then you feel the frustration of using Jackson.

Add in some web annotations, security annotations, ORM annotations, logging, test annotations and so on and it's the same story -- you are in fact doing something very complex and when you depart from the happy path of using the functionality via annotations, it gets quite frustrating.

I really don't know anything "better"(time wise) to accomplish the same thing though.