use ConcurrentHashMap to replace Collections.synchronizedMap(HashMap) ?

[Roger Riggs]

Hi,

There's usually a 'it depends' in questions like this.

ConcurrentHashMap *does NOT allow null *keys or values. HashMap *does 
allow null* as keys and values.

And more obviously, using a synchronized HashMap does not allow any 
concurrency.
ConcurrentHashMap is built to allow concurrent access.

Regards, Roger

On 20/04/2022 14:26, Xeno Amess wrote:
> Collections.synchronizedMap(new HashMap<Integer, byte[]>())
>
> new ConcurrentHashMap <Integer, byte[]>  ()
>
> Is the later one always better than the first one?
>
> I personally think so, but are there any traps in it?