git: openjdk/jdk21u-dev: master: 8351000: StringBuilder getChar and putChar robustness

[Goetz Lindenmaier]

Changeset: 9f0c5be7
Branch: master
Author:    Goetz Lindenmaier <goetz at openjdk.org>
Date:      2025-12-17 08:59:40 +0000
URL:       https://git.openjdk.org/jdk21u-dev/commit/9f0c5be77fe06e1a5ad9c93f202f4c72e1981347

8351000: StringBuilder getChar and putChar robustness

Reviewed-by: rschmelter
Backport-of: 4c695fa8a459adcdb8cdfe9e90783007c65fb90e

! src/java.base/share/classes/java/lang/AbstractStringBuilder.java
+ test/jdk/java/lang/StringBuilder/RacingSBThreads.java