This program:

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import java.util.*;
import java.util.concurrent.*;

public class Perf {
    public static void main(String[] args) throws Throwable {
final int n = 3;
final ScheduledThreadPoolExecutor pool
= new ScheduledThreadPoolExecutor(3);
pool.setExecuteExistingDelayedTasksAfterShutdownPolicy(true);
ScheduledFuture<?> future = pool.schedule(
new Runnable() { public void run() {
System.out.println("Hey!");}},
1L, TimeUnit.MINUTES);

pool.shutdown();
pool.awaitTermination(1L, TimeUnit.HOURS);
    }
}
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uses up lots of CPU:

 jver mustang jr Perf
==> javac -source 1.6 -Xlint:all Perf.java
==> java -esa -ea Perf
Hey!
jver mustang jr Perf 48.45s user 0.42s system 75% cpu 1:04.44 total