public class Job {
    void run() {
        System.out.println("Running a Job in " + System.currentTimeMillis()/ 1000 + " sec.");
    }
}

public class JobRunner {

    private class Task {
        Job job;
        long timeToRun;
        public Task(Job job, long timeToRun) {
            this.job = job;
            this.timeToRun = timeToRun;
        }
    }

    private PriorityQueue<Task> queue;
    private Thread runnerThread;

    public JobRunner() {
        queue = new PriorityQueue<Task>(new Comparator<Task>() {
            public int compare(Task a, Task b) {
                return (int) Long.compare(a.timeToRun, b.timeToRun);
            }
        });
        runnerThread = new Thread(new Runnable() {
            public void run() {
                long time = 1000;
                while (true) {
                    synchronized(queue) {
                        try {
                            queue.wait(time);
                        } catch (InterruptedException e) {}

                        if (queue.isEmpty()) {
                            time = 1000;
                        } else {
                            if (queue.peek().timeToRun <= System.currentTimeMillis() / 1000) {
                                Task task = queue.poll();
                                task.job.run();
                                time = 1; // only wait for 1 millis and return immediately
                            } else {
                                time = queue.peek().timeToRun * 1000 - System.currentTimeMillis();
                            }
                        }
                    }
                }
            }
        });
        runnerThread.start();
    }

    public void submit(Job job, long delayInSec) {
        synchronized(queue) {
            queue.offer(new Task(job, delayInSec + System.currentTimeMillis() / 1000));
            queue.notify();
        }
    }

    public static void main(String[] args) {
        JobRunner runner = new JobRunner();
        Job job1 = new Job();
        Job job2 = new Job();
        Job job3 = new Job();
        runner.submit(job1, 10);
        runner.submit(job2, 1);
        runner.submit(job3, 2);
    }
}