Sun Java System Application Server Enterprise Edition 8.1 2005Q2 Administration Guide

About Thread Pools

This section describes thread pools and how the work in the Application Server.

The Java Virtual Machine (JVM) can support many threads of execution at once. To help performance, the Application Server maintains one or more thread pools. It is possible to assign specific thread pools to connector modules and to the ORB.

One thread pool can serve multiple connector modules and enterprise beans. Request threads handle user requests for application components. When the server receives a request, it assigns the request to a free thread from the thread pool. The thread executes the client's requests and returns results. For example, if the request needs to use a system resource that is currently busy, the thread waits until that resource is free before allowing the request to use that resource.

Specify the minimum and maximum number of threads that are reserved for requests from applications. The thread pool is dynamically adjusted between these two values. The minimum thread pool size that is specified signals the server to allocate at least that many threads in reserve for application requests. That number is increased up to the maximum thread pool size that is specified.

Increasing the number of threads available to a process allows the process to respond to more application requests simultaneously.

Avoid thread starvation, where one resource adapter or application occupies all threads in the Application Server, by dividing the Application Server threads into different thread-pools.