1 public class Main {
main(String[] args)2     static public void main(String[] args) throws Exception {
3         int millis = 1000;
4 
5         if (args.length > 1) {
6             millis = Integer.parseInt(args[1]);
7         }
8 
9         System.out.println("Sleeping " + millis + " msec...");
10 
11         long start = System.currentTimeMillis();
12         Thread.sleep(millis);
13         long elapsed = System.currentTimeMillis() - start;
14         long offBy = Math.abs(elapsed - millis);
15 
16         System.out.println("Done sleeping");
17 
18         if (offBy > 250) {
19             System.out.println("Actually slept about " + elapsed + " msec...");
20         }
21     }
22 }
23