Are there any liveness issues about thread scheduling in the JVM?

David Holmes david.holmes at
Sun Jul 15 17:55:02 PDT 2012

On 10/07/2012 9:20 PM, Xie Xiaodong wrote:
> We are facing some interesting behavior in production.
> Here are some thread dumps taken at different time. During this period,
> only httpSSLWorkerThread-10080-99 can make progress. Other threads were
> always stuck in the synchronization point. And "waiting to lock
> <0x75b395d8>", this hex number changed several times. What does this number
> mean?

An example:

- waiting to lock <0x75b395d8> (a casinomodule.util.TimeUtilImpl)

The number is the address of an object that the threads are trying to 
lock. It is an instance of casinomodule.util.TimeUtilImpl. If the 
address, for a given thread, keeps changing, it means that the threads 
are in fact making progress, as they must have locked object form the 
previous stack dump and then moved on to the current one. If the number 
is different for different threads then they are simply trying to lock 
different objects.

There would appears to be a synchronization bottleneck in this 


> Thanks a lot for your time.

More information about the hotspot-dev mailing list