Thanks - you're right - I filed https://bugs.openjdk.java.net/browse/JDK-8190889 On Tue, Nov 7, 2017 at 2:25 PM, Christoph Dreis <christoph.dreis@freenet.de> wrote:

Hi,

I don't know if this is considered a real bug or just a lack of documentation, but I found that although the example in the documentation of TimeUnit.timedWait(Object obj, long timeout) shows the correct usage of the method, I think at least the documentation should emphasize the possibility of an IllegalMonitorStateException in case it isn't executed inside a synchronized block.

The method seems to be not used inside the JDK itself after all, but people might use it.

Please find a minimal reproduction and a possible documentation patch below. In case it is considered worthwhile I'd be happy if this is sponsored.

Cheers, Christoph

===== MINIMAL REPRO ====== public class Main {

public static void main(String[] args) { Lock lock = new ReentrantLock(); try { TimeUnit.MILLISECONDS.timedWait(lock, 1); } catch (InterruptedException e) { e.printStackTrace(); } }

}

====== PATCH ========== diff -r 67aa34b019e1 src/java.base/share/classes/java/util/concurrent/TimeUnit.java --- a/src/java.base/share/classes/java/util/concurrent/TimeUnit.java Mon Nov 06 17:48:00 2017 -0800 +++ b/src/java.base/share/classes/java/util/concurrent/TimeUnit.java Tue Nov 07 23:09:24 2017 +0100 @@ -356,6 +356,8 @@ * @param timeout the maximum time to wait. If less than * or equal to zero, do not wait at all. * @throws InterruptedException if interrupted while waiting + * @throws IllegalMonitorStateException if not executed inside a + * synchronized block */ public void timedWait(Object obj, long timeout) throws InterruptedException {