RFR: 8035584: (s) ArrayList(c) should avoid inflation if c is empty

Martin Buchholz martinrb at google.com
Fri Feb 21 22:59:26 UTC 2014

You accidentally deleted a stray space here?

-        this.elementData = EMPTY_ELEMENTDATA;
+       this.elementData = EMPTY_ELEMENTDATA;

On Fri, Feb 21, 2014 at 2:41 PM, Mike Duigou <mike.duigou at oracle.com> wrote:

> Hello all;
> This changeset consists of two small performance improvements for
> ArrayList. Both are related to the lazy initialization introduced in
> JDK-8011200.
> The first change is in the ArrayList(int capacity) constructor and forces
> lazy initialization if the requested capacity is zero. It's been observed
> that in cases where zero capacity is requested that it is very likely that
> the list never receives any elements. For these cases we permanently avoid
> the allocation of an element array.
> The second change, noticed by Gustav Åkesson, involves the
> ArrayList(Collection c) constructor. If c is an empty collection then there
> is no reason to inflate the backing array for the ArrayList.
> http://cr.openjdk.java.net/~mduigou/JDK-8035584/0/webrev/
> I also took the opportunity to the <tt></tt> -> {@code } conversion for
> the javadoc.
> Enjoy!
> Mike

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