On Fri, 11 Apr 2025 17:31:08 GMT, Johannes Graham <[email protected]> wrote:
> The `DigitList` class used in `DecimalFormat` does not reset the `data` array
> in its clone method. This can cause interference when clones are used
> concurrently.
Reproducing code example:
public class DecimalFormatTest {
static AtomicInteger mismatchCount = new AtomicInteger(0);
public static void main(String[] args) {
DecimalFormat df = new DecimalFormat("#");
String str = df.format(Math.PI); // initial use of formatter
System.out.println(str);
try (var ex =
Executors.newThreadPerTaskExecutor(Thread.ofPlatform().factory())) {
for (int i = 0; i < 50; i++) {
// each thread gets its own clone of df
DecimalFormat threadDf = (DecimalFormat) df.clone();
ex.execute(makeTask(threadDf));
}
}
System.out.println("mismatchCount = " + mismatchCount);
}
private static Runnable makeTask(DecimalFormat threadDf) {
return () -> {
for (int i = 0; i < 1000000; i++) {
String dfString = threadDf.format(BigDecimal.valueOf(i));
String str = String.valueOf(i);
if (!str.equals(dfString)) {
System.err.println("mismatch: str = " + str + " dfString =
" + dfString);
mismatchCount.incrementAndGet();
}
}
};
}
}
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PR Comment: https://git.openjdk.org/jdk/pull/24598#issuecomment-2797607528
