HN user
I took a look at lombok and it's pretty obvious from the way cleanup method names can be passed as strings that's it's using reflection. It's a bit of a nasty hack, but it works.
I think the only thing that was added to the API was a single interface called Closeable. Adding 1 interface to a library is hardly bloat. The change is essentially language support for a common syntax for resource management, not a new API.
Rough example below, partially taken from a book I have on Scala.
//define it like this: def using[T <: {def close(): Unit }, S](obj: T) (operation: T => S) = { val result = operation(obj) obj.close() result }
//use it like this: val writer = new FunkyWriter using(writer) { writer.write("outputting some data") }
ARM was therefore possible in Scala before the Closable interface was even added to the Java libs.