ExecutorService example

ExecutorService executor = Executors.newFixedThreadPool(pool_size);
for(...){
  OSA_Worker worker = new OSA_Worker();//OSA_Worker implements Runnable interface
  executor.execute(worker);
}

executor.shutdown();//不再加入新的线程

//等待执行完成
while (!executor.isTerminated()) {
	Thread.sleep(1000);
}