ThreadPoolTaskExecutor Getting Overwritten in Scheduled Class - spring-boot

Question

I have the following ThreadPoolTaskExecutor thats gets created with the expected core/max pool size configurations.
#Slf4j
#Configuration
public class ThreadPoolConfig {
#Value("${corePoolSize}")
private Integer corePoolSize;
#Value("${queueCapacity}")
private Integer queueCapacity;
#Value("${maxPoolSize}")
private Integer maxPoolSize;
#Bean(name="myThreadPoolTaskExecutor")
public ThreadPoolTaskExecutor myThreadPoolTaskExecutor() {
ThreadPoolTaskExecutor executor = new ThreadPoolTaskExecutor();
executor.setBeanName("myThreadPoolTaskExecutor");
executor.setCorePoolSize(corePoolSize);
executor.setQueueCapacity(queueCapacity);
executor.setMaxPoolSize(maxPoolSize);
executor.setThreadNamePrefix("my_thread_");
executor.setWaitForTasksToCompleteOnShutdown(true);
executor.initialize();
log.debug("threadPoolTaskExecutor CorePoolSize is : " + executor.getCorePoolSize());
log.debug("threadPoolTaskExecutor MaxPoolSize is : " + executor.getMaxPoolSize());
return executor;
}
}
When my #scheduled method runs the max pool size is set to the DEFAULT value of 2147483647 and I don't understand why it's not using the configured ThreadPoolTaskExecutor above:
#EnableScheduling
public class SchedulingConfig {
}
#Component
public class Scheduler {
#Autowired
#Qualifier("myThreadPoolTaskExecutor")
private ThreadPoolTaskExecutor threadPoolTaskExecutor;
#Scheduled(fixedRateString = "${fixedRate}")
public void invokeScheduledThread() {
while (threadPoolTaskExecutor.getActiveCount() <= threadPoolTaskExecutor.getMaxPoolSize()) {
log.debug("Active Thread Pool count is : " + threadPoolTaskExecutor.getActiveCount() + ", Max Thread Pool count is : " + threadPoolTaskExecutor.getMaxPoolSize() + " on the scheduled Thread : " + Thread.currentThread().getName());
//call a service to retrieve some items to process
threadPoolTaskExecutor.execute(Some Object that implements runnable);
}
}
}
Output:
Active Thread Pool count is : 0, Max Thread Pool count is : 2147483647 on the scheduled Thread : task-scheduler-1
I put a break point into the initialise() method of org.springframework.scheduling.concurrent.ExecutorConfigurationSupport
and it looks like the method is getting invoked 3 times, twice with a ThreadName Prefix of "my_thread_"
which is expected and finally once for a Bean called "taskScheduler" with a ThreadName Prefix of "task-scheduler-".
Does anyone know why I can't use my own ThreadPoolTaskExecutor within the Scheduler class?
I wanted to use a default #Scheduler to run on a single thread every x number of seconds and create X number of Threads using my own ThreadPoolTaskExecutor.

Answer 1

Use ThreadPoolTaskScheduler instead of ThreadPoolTaskExecutor.
For example:
#Configuration
public class SpringSchedulerConfig {
private static final int THREAD_POOL_SIZE = 5;
#Bean
public ThreadPoolTaskScheduler getScheduler() {
ThreadPoolTaskScheduler threadPoolTaskScheduler = new ThreadPoolTaskScheduler();
//we want every Job in a separate Thread.
threadPoolTaskScheduler.setPoolSize(THREAD_POOL_SIZE);
return threadPoolTaskScheduler;
}
}