why grails uses "static" vars instead of annotations

Question

for example:class

Book {
static mapping = {
 batchSize 10
}
}

could be:

@Configration(batchSize=10)
class Book {
    ...
}

Answer 1

Maybe because they can be changed that way? And annotations are set in stone.

Answer 2

The main reason is that Grails was developed for Groovy 1.1 which didn't support annotations. I guess one of the next versions will support annotations but as alamar said, annotations can't be changed at runtime. Therefore, the current approach is more flexible.