Synchronization does only work per-JVM.  (Consider that you're synchronizing
on an object: that same object cannot possibly appear in two different
JVMs.)

The only work-around is to do locking yourself, using some resource (like a
file, a database, a servlet, or an RMI server) which is accessible from all
server machines/processes.

                                                            -- Bill K.


> -----Original Message-----
> From: Nico Wieland [mailto:wieland@netvertising.ch]
> Sent: Monday, April 02, 2001 8:40 AM
> To: tomcat-user@jakarta.apache.org
> Subject: load balancing and synchronization
> 
> 
> hi list
> 
> if i do load balancing with tomcat (w/ mod_jk), what happens 
> if the two tomcat servers at the same time execute a 
> synchronized method? will they know that they mustn't execute 
> it concurrently or not? if synchronization worked only per 
> JVM, would there be a workaround?
> 
> thanks,
> 
> -nico
> 
> 
> Nico Wieland
> 
> NETVERTISING AG    Agentur fuer zeitgerechte Kommunikation
> Samariterstrasse 5, CH 8032 Zuerich
> Telefon +41 1 267 11 11,  Fax +41 1 267 11 99
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> 
>