Question

I try to avoid vars in my code where possible for easier multithreading. However there is one line of code that starts:

val positions: Hashtable[String, String] ...

I’m wondering does the val make things automagically thread safe or are there further details that I need to worry about?

Answer 1

By prefixing positions with a val you make it immutable. By “it” I mean the reference to the Hashtable and not the Hashtable itself and therefore by “immutable” I mean you cannot assign another Hashtable to positions.

So the Hashtable itself can change over time, but positions will always point to it. Nothing is automagically threadsafe.