Java anon classes couldn't capture non-final locals back when they were introduced. So they were closures, but not full-fledged. In contrast, C# anon delegates could capture any local, including writeable ones.
They still can't, captured variables need to be "effectively final" since Java 8, meaning they aren't allowed to be written after the capture.
I think that's reasonable though, capturing mutable state is a recipe for disaster, and if you really want/need to you can wrap it in a properly synchronized container (e.g. AtomicReference in Java)
