RFR 8214971 : Replace use of string.equals("") with isEmpty()

[James Laskey]

Or simply;

if (anObject instanceof String) {
           String aString = (String)anObject;
           if (coder() == aString.coder())
                return Arrays.equals(value, aString.value);
           }
       }

Sent from my iPhone

> On Dec 6, 2018, at 10:56 PM, Stuart Marks <stuart.marks at oracle.com> wrote:
> 
>> 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