Dynamic Thread Pool

Question

I have a long running process that listens to events and do some intense processing.

Currently I use Executors.newFixedThreadPool(x) to throttle the nu

Answer 1

Have a look at below API in ThreadPoolExecutor

public void setCorePoolSize(int corePoolSize)

Sets the core number of threads. This overrides any value set in the constructor.

If the new value is smaller than the current value, excess existing threads will be terminated when they next become idle.

If larger, new threads will, if needed, be started to execute any queued tasks.

Initialization:

ExecutorService service = Executors.newFixedThreadPool(5); 

On need basis, resize Thread pool by using below API

((ThreadPoolExecutor)service).setCorePoolSize(newLimit);//newLimit is new size of the pool 

Important note:

If the queue is full, and new value of number of threads is greater than or equal to maxPoolSize defined earlier, Task will be rejected.

So set values of maxPoolSize and corePoolSize properly.