I need to scale calls into Tomcat and it\'s been suggested to launch threads internally. Has anyone needed to do this and, if so, what solutions did they come up with?
What is the problem you are trying to solve with threads?
If have long running tasks you should use JMS + a full Java EE container.
If you trying to handle excess load you could consider two tomcat instances, however, if you are using http sessions you will need to investigate session replication.
If you are forced to use Tomcat consider using the Executors framework in java.util.concurrency.