Threading fun!!!

TestingExecutorService.java

package testex;

import java.util.ArrayList;
import java.util.List;
import java.util.concurrent.ArrayBlockingQueue;
import java.util.concurrent.Callable;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.RejectedExecutionHandler;
import java.util.concurrent.ThreadPoolExecutor;
import java.util.concurrent.TimeUnit;

public class TestingExecutorService {
	// making this object as static as you don't want multiple services created
	// for each request
	static ExecutorService executor = new ThreadPoolExecutor(1, 1,
			1, TimeUnit.SECONDS,
			new ArrayBlockingQueue<Runnable>(100),
			new RejectedExecutionHandler() {
				@Override
				public void rejectedExecution(Runnable r,
						ThreadPoolExecutor executor) {
					System.out.println("Execution rejected");
					try {
						executor.getQueue().put(r);
					} catch (InterruptedException e) {
						throw new RuntimeException(
								"Interrupted while submitting task", e);
					}
				}
			});

	public static void main(String[] args) throws InterruptedException {
		new TestingExecutorService().doTask();
		new TestingExecutorService().doTask();
		Thread.sleep(5000);
		new TestingExecutorService().doTask();

	}

	public void doTask() {

		System.out.println("doTask()");
		System.out.println("Completed tasks "
				+ ((ThreadPoolExecutor) executor).getCompletedTaskCount());
		System.out.println("Total threads in execution"
				+ ((ThreadPoolExecutor) executor).getPoolSize());
		System.out.println("Scheduled tasks "
				+ ((ThreadPoolExecutor) executor).getTaskCount());
		// Creating separate Callable thread job wrapping tasks
		// job for non-blocking execution
		ExecutorJob task = new ExecutorJob();
		List<Callable<String>> executorJobs = new ArrayList<Callable<String>>();
		executorJobs.add(task);

		// submitting jobs to executor for non-blocking execution
		for (Callable<String> job : executorJobs) {
			executor.submit(job);
		}
		//executor.shutdown(); //if shutdown gets called - no more tasks are accepted
		
		Runtime.getRuntime().addShutdownHook(new Thread() {
		    public void run() {
		    	List<Runnable> droppedTasks = executor.shutdownNow(); 
	            System.out.println("Shutdown hook called. Dropped tasks: "+droppedTasks.size());
		    }
		});
	}

	private class ExecutorJob implements Callable<String> {

		public String call() throws Exception {
			System.out.println("task started");
			Thread.sleep(1000);
			System.out.println("task finished");
			return null;
		}
	}
}