RFR 8214971 : Replace use of string.equals("") with isEmpty()
Stuart Marks
stuart.marks at oracle.com
Fri Dec 7 02:56:00 UTC 2018
On 12/6/18 2:42 PM, Claes Redestad wrote:
> I filed this bug after seeing it in startup profiles, where isEmpty() avoids an
> instanceof and four(!) method calls, so getting rid of a few of these has a
> measurable impact on startup. It seemed prudent to just replace it all while
> we're at it.
Interesting. The compact strings stuff saves a lot of space, but it means that
more setup work needs to be done before an actual equality comparison can be
done. Thus, equals("") has gotten quite a bit more expensive relative to
isEmpty() compared with the situation prior to compact strings.
Still, it seems like a method call could be saved here:
if (anObject instanceof String) {
String aString = (String)anObject;
if (coder() == aString.coder()) {
return isLatin1() ? StringLatin1.equals(value, aString.value)
: StringUTF16.equals(value, aString.value);
}
}
by saving the result of coder() in a local variable and then comparing it
directly to LATIN1. Is it worth it?
(Note, this isn't relevant to the current review.)
s'marks
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