<pre>  <code class="language-java">  package mythread;    public class CountOperate extends Thread{        public CountOperate(){          System.out.println("CountOperate---begin");          System.out.println("Thread.currentThread().getName()=" + Thread.currentThread().getName());//获取线程名          System.out.println("Thread.currentThread().isAlive()=" + Thread.currentThread().isAlive()); //查看线程是否存活          System.out.println("this.getName=" + this.getName());           System.out.println("this.isAlive()=" + this.isAlive());          System.out.println("CountOperate---end ");          System.out.println("Thread.currentThread()==this :"+ (Thread.currentThread() == this));      }        @Override      public void run() {          System.out.println("run---begin");          System.out.println("Thread.currentThread().getName=" + Thread.currentThread().getName());          System.out.println("Thread.currentThread().isAlive()" + Thread.currentThread().isAlive());          System.out.println("Thread.currentThread()==this :"+ (Thread.currentThread() == this));          System.out.println("this.getName()=" + this.getName());          System.out.println("this.isAlive()=" + this.isAlive());          System.out.println("run --- end");      }  }  </code></pre>    <pre>  <code class="language-java">   public class Run {        public static void main(String[] args){            CountOperate c = new CountOperate();          c.start();          Thread t1 = new Thread(c);          System.out.println("main begin t1 isAlive=" + t1.isAlive());          t1.setName("A");          t1.start();          System.out.println("main end t1 isAlive=" + t1.isAlive());        }  }  </code></pre>    <p>打印的log为:</p>    <pre>  <code class="language-java">CountOperate---begin  Thread.currentThread().getName()=main  Thread.currentThread().isAlive()=true  this.getName=Thread-0  this.isAlive()=false  CountOperate---end   Thread.currentThread()==this :false  main begin t1 isAlive=false  main end t1 isAlive=true  run---begin  Thread.currentThread().getName=A  Thread.currentThread().isAlive()true  Thread.currentThread()==this :false  this.getName()=Thread-0  this.isAlive()=false  run --- end    </code></pre>    <p>根据打印的Log可以知道调用CountOperate构造函数的是main线程，因此打印出</p>    <pre>  <code class="language-java">Thread.currentThread().getName()=main  Thread.currentThread().isAlive()=true  而此时还没有启动CountOperate子线程所以打印出</code></pre>    <pre>  <code class="language-java">this.getName=Thread-0  this.isAlive()=false    此时this代表的是CountOperate对象实例，所以</code></pre>    <pre>  <code class="language-java">Thread.currentThread()==this :false    这里比较让人疑惑的是“this.getName() = Thread-0”，这个Thread-0是什么东西？？？ </code></pre>    <pre>  <code class="language-java">通过查看Thread源码发现，在Thread类的构造方法中，会自动给name赋值，赋值代码：</code></pre>    <p><img src="https://simg.open-open.com/show/ad2c253030d7ada36ca306bf95fc5d6e.png"></p>    <pre>  <code class="language-java">然后执行到:</code></pre>    <pre>  <code class="language-java">Thread t1 = new Thread(c);  System.out.println("main begin t1 isAlive=" + t1.isAlive());  t1.setName("A");  t1.start();    Log打印：  Thread.currentThread().getName=A  Thread.currentThread().isAlive()true  Thread.currentThread()==this :false  this.getName()=Thread-0  this.isAlive()=false  说明此时的this和Thread.currentThread()指向不是同一个线程实例    也就是说，this指向的还是new CountOperate()创建的那个线程实例，而不是new Thread(thread)创建的那个实例即t1。  查看源代码可以知道。  <img alt="" src="https://simg.open-open.com/show/0fdbdeea2b522baae2041fa16032733d.png">  实际上new Thread(thread)会将thread应用的对象绑定到一个pravite变量target上，  在t1被执行的时候即t1.run()被调用的时候，它会调用target.run()方法，也就是说它是直接调用thread对象的run方法，  再确切的说，在run方法被执行的时候，this.getName()实际上返回的是target.getName()，而Thread.currentThread().getName()实际上是t1.getName()。    因此我们修改下main中的代码为:  </code></pre>    <pre>  <code class="language-java">public class Run {        public static void main(String[] args){            CountOperate c = new CountOperate();          c.start();      }  }  </code></pre>    <p>打印的log为:</p>    <pre>  <code class="language-java">CountOperate---begin  Thread.currentThread().getName()=main  Thread.currentThread().isAlive()=true  this.getName=Thread-0  this.isAlive()=false  CountOperate---end   Thread.currentThread()==this :false  run---begin  Thread.currentThread().getName=Thread-0  Thread.currentThread().isAlive()true  Thread.currentThread()==this :true  this.getName()=Thread-0  this.isAlive()=true  run --- end  </code></pre>    <p>与我们预想的结果相同</p>    <p> </p>    <p>来自：http://www.cnblogs.com/huangyichun/p/6071625.html</p>    <p> </p>