Java 9中Thread.onSpinWait()方法的重要性是什么？

<strong>public static void onSpinWait()</strong>

public class ThreadOnSpinWaitTest {
   public static void main(final String args[]) throws InterruptedException {
      final NormalTask task1 = new NormalTask();
      final SpinWaitTask task2 = new SpinWaitTask();
      final Thread thread1 = new Thread(task1);
      thread1.start();
      final Thread thread2 = new Thread(task2);
      thread2.start();
      new Thread(() -> {
         try {
            Thread.sleep(1000);
         } catch(final InterruptedException e) {
            e.printStackTrace();
         } finally {
            task1.start();
            task2.sta*rt();
         }
      }).start();
      thread1.join();
      thread2.join();
   }
   private <strong>abstract </strong>static class Task implements Runnable {
      volatile boolean canStart;
      void start() {
         this.canStart = true;
      }
   }
   private <strong>static </strong>class NormalTask extends Task {
      <strong>@Override</strong>
      public void run() {
         while(!this.canStart) {
         }
         System.out.println("Done!");
      }
   }
   private <strong>static </strong>class SpinWaitTask extends Task {
      <strong>@Override</strong>
      public void run() {
         while(!this.canStart) {
            Thread.<strong>onSpinWait()</strong>;
         }
         System.out.println("Done!");
      }
   }
}

<strong>Done!
Done!</strong>