8229022: BufferedReader performance can be improved by using StringBuilder

[Vyom Tiwari]

Hi Brian,
Looks good to me.
thanks,
Vyom

On Wed, Oct 2, 2019 at 5:44 AM Brian Burkhalter <brian.burkhalter at oracle.com>
wrote:

> While the performance improvement that I measured for this proposed change
> [1] using JMH was only in the 2% to 8% range as opposed to the 13% claimed
> in the issue description, given the simplicity of the change [2] it is
> probably worth doing. All use of the StringBuilder is within a synchronized
> block within a single package-scope method, so there should be no problem
> with access by multiple threads.
>
> Thanks,
>
> Brian
>
> [1] https://bugs.openjdk.java.net/browse/JDK-8229022
> [2] diff
>
> --- a/src/java.base/share/classes/java/io/BufferedReader.java
> +++ b/src/java.base/share/classes/java/io/BufferedReader.java
> @@ -314,7 +314,7 @@
>       * @throws     IOException  If an I/O error occurs
>       */
>      String readLine(boolean ignoreLF, boolean[] term) throws IOException {
> -        StringBuffer s = null;
> +        StringBuilder s = null;
>          int startChar;
>
>          synchronized (lock) {
> @@ -372,7 +372,7 @@
>                  }
>
>                  if (s == null)
> -                    s = new StringBuffer(defaultExpectedLineLength);
> +                    s = new StringBuilder(defaultExpectedLineLength);
>                  s.append(cb, startChar, i - startChar);
>              }
>          }
>
>

-- 
Thanks,
Vyom