Spring ThreadPoolTaskExecutor never grows beyond corePoolSize

java, multithreading, spring, threadpool

Solution

Got it:

If there are more than corePoolSize but less
than maximumPoolSize threads running,
a new thread will be created only if the queue is full.

So the solution is to shrink the queue!

Problem

I have configured Spring ThreadPoolTaskExecutor, having in mind 16 threads at least and up to 256 on the need-basis: ``` <bean id="taskExecutor" class="org.springframework.scheduling.concurrent.ThreadPoolTaskExecutor"> <property name="corePoolSize" value="16"/> <property name="maxPoolSize" value="256"/> <property name="queueCapacity" value="256"/> </bean> ``` But as I can see from logs, thread pool size never exceeds corePoolSize: ``` Thread pool size: 16/256, active count: 16 ``` Why is that so? What have I done wrong?

Original source