What is the closest to ConcurrentHashMap and NavigableMap in Java?

[SomeDude]

On Friday, 15 November 2013 at 22:22:32 UTC, Jacek Furmankiewicz 
wrote:
> So....how does Facebook handle it with their new D code?
>
> No GC at all, explicit memory management?

AFAWK, Facebook doesn't use D for its core business yet, only for 
buiding tools. OTOH, Andrei has been working hard on memory 
allocators, so maybe that's one idea that they are digging.