About Question enthuware.ocpjp.v7.2.1536 :

[sinapse]

Hi,
why synchronized (this)
is not a good option here ?

Thanks

[admin]

Synchronizing on "this" will synchronize on the Producer instance and Consumer instance, not on the data instance. So producer thread and consumer threads will be able to access data simultaneously, which you do not want.

HTH,
Paul.