The spec says that "".hashCode() must be 0. https://docs.oracle.com/en/java/javase/11/docs/api/java.base/java/lang/String.html#hashCode()
On Mon, Apr 1, 2019 at 12:51 PM <dean.l...@oracle.com> wrote: > Wouldn't it be better to write a non-0 value when the computed hash code > is 0, so we don't have to recompute it? Is there some advantage to > writing 0 instead of any other value, such as 1? > > dl > > On 4/1/19 4:57 AM, Claes Redestad wrote: > > Hi, > > > > when a String has a calculated hash code value of 0, we recalculate and > > store a 0 to the String.hash field every time (except for the empty > > String, which is special cased). To make String objects more amenable to > > storage in shared read-only memory, e.g., CDS archives, we should avoid > > this redundant store. > > > > Bug: https://bugs.openjdk.java.net/browse/JDK-8221723 > > Webrev: http://cr.openjdk.java.net/~redestad/8221723/ > > > > Testing: tier1-3, no regression on existing and new StringHashCode > > micros > > > > /Claes > > > >
