I20220209-1800
Don't allow multiple threads to call PackageNameSet add() and rehash() methods simultaneously. Change-Id: I5109fdfcc8cacf225f230240328a886db3215b31 Reviewed-on: https://git.eclipse.org/r/c/jdt/eclipse.jdt.core/+/190613 Tested-by: JDT Bot <jdt-bot@eclipse.org> Reviewed-by: Andrey Loskutov <loskutov@gmx.de>