在Java中，线程优先级的重要性是什么？

public final int getPriority()

public class ThreadPriorityTest extends Thread {
   public static void main(String[]args) {
      ThreadPriorityTest thread1 = new ThreadPriorityTest();
      ThreadPriorityTest thread2 = new ThreadPriorityTest();
      ThreadPriorityTest thread3 = new ThreadPriorityTest();
      System.out.println("Default thread priority of thread1: " + thread1.<strong>getPriority</strong>());
      System.out.println("Default thread priority of thread2: " + thread2.<strong>getPriority</strong>());
      System.out.println("Default thread priority of thread3: " + thread3.<strong>getPriority</strong>());
      thread1.setPriority(8);
      thread2.setPriority(3);
      thread3.setPriority(6);
      System.out.println("New thread priority of thread1: " + thread1.<strong>getPriority()</strong>);
      System.out.println("New thread priority of thread2: " + thread2.<strong>getPriority()</strong>);
      System.out.println("New thread priority of thread3: " + thread3.<strong>getPriority()</strong>);
   }
}

Default thread priority of thread1: 5
Default thread priority of thread2: 5
Default thread priority of thread3: 5
New thread priority of thread1: 8
New thread priority of thread2: 3
New thread priority of thread3: 6