Proposal: ArrayList constructor perforrmance improvement

[Martin Buchholz]

Thanks as always to Jason, our master Historian.

On Wed, Dec 19, 2018 at 2:14 AM Steve Groeger <GROEGES at uk.ibm.com> wrote:

>
> Yes, the intent was to leave the backing array the same size in order to
> avoid to have the resize of it when a new element is added.
> So, if someone wanted to reduce the size of the backing array then they
> could use the ArrayList.trimToSize() method.


If you knew you wanted to add exactly one element after making a copy, an
(distasteful but effective) performance hack might be to add the element to
the source ArrayList, copy using ArrayList(Collection) and then remove the
element from the source.