I was looking through a [Findbugs](http://findbugs.sourceforge.net/) report on my code base and one of the patterns that was triggered was for an empty `synchronzied` block (i.e. `synchronized (var) {}`). The [documentation says](http://findbugs.sourceforge.net/bugDescriptions.html#ESync_EMPTY_SYNC):

> 
> Empty synchronized blocks are far more
>  subtle and hard to use correctly than
>  most people recognize, and empty
>  synchronized blocks are almost never a
>  better solution than less contrived
>  solutions.
> 
> 
> 

In my case it occurred because the contents of the block had been commented out, but the `synchronized` statement was still there. In what situations could an empty `synchronized` block achieve correct threading semantics?