The Executor (thread pool)

The Executor represents a thread pool that can be shared between components in Tomcat. Historically there has been a thread pool per connector created but this allows you to share a thread pool, between (primarly) connector but also other components when those get configured to support executors

The executor has to implement the org.apache.catalina.Executor interface.

The executor is a nested element to the Service element. And in order for it to be picked up by the connectors, the Executor element has to appear prior to the Connector element in server.xml

All implementations of Executor support the following attributes:

The class of the implementation. The implementation has to implement the org.apache.catalina.Executor interface. This interface ensures that the object can be referenced through its name attribute and that implements Lifecycle, so that it can be started and stopped with the container. The default value for the className is org.apache.catalina.core.StandardThreadExecutor

The name used to reference this pool in other places in server.xml. The name is required and must be unique.

The default implementation supports the following attributes:

(int) The thread priority for threads in the executor, the default is Thread.NORM_PRIORITY

(boolean) Whether the threads should be daemon threads or not, the default is true

(String) The name prefix for each thread created by the executor. The thread name for an individual thread will be namePrefix+threadNumber

(int) The max number of active threads in this pool, default is 200

(int) The minimum number of threads always kept alive, default is 25

(int) The number of milliseconds before an idle thread shutsdown, unless the number of active threads are less or equal to minSpareThreads. Default value is 60000(1 minute)