if i have got such java code:
public static void main(String[] args) { for(int i = 0;i<100;i++) { Future> f = ThreadPoolManager.getIns
cancel(true) calls interrupt() on your thread, nothing more. So, you need to handle it properly in your run() method. For your simple case your threads will finish their execution and their objects will be cleared by GC.
cancel(true)
interrupt()
run()