import java.lang.reflect.Field;
 import java.util.concurrent.ArrayBlockingQueue;
 import java.util.concurrent.ThreadPoolExecutor;
 import java.util.concurrent.TimeUnit;
 import java.util.concurrent.ThreadPoolExecutor.DiscardPolicy;
 
 public class DiscardPolicyDemo {
 
   private static final int THREADS_SIZE = 1;
   private static final int CAPACITY = 1;
 
   public static void main(String[] args) throws Exception {
 
     // 创建线程池。线程池的"最大池大小"和"核心池大小"都为1(THREADS_SIZE)，"线程池"的阻塞队列容量为1(CAPACITY)。
     ThreadPoolExecutor pool = new ThreadPoolExecutor(THREADS_SIZE, THREADS_SIZE, 0, TimeUnit.SECONDS,
         new ArrayBlockingQueue<Runnable>(CAPACITY));
     // 设置线程池的拒绝策略为"丢弃"
     pool.setRejectedExecutionHandler(new ThreadPoolExecutor.DiscardPolicy());
 
     // 新建10个任务，并将它们添加到线程池中。
     for (int i = 0; i < 10; i++) {
       Runnable myrun = new MyRunnable("task-"+i);
       pool.execute(myrun);
     }
     // 关闭线程池
     pool.shutdown();
   }
 }
 
 class MyRunnable implements Runnable {
   private String name;
   public MyRunnable(String name) {
     this.name = name;
   }
   @Override
   public void run() {
     try {
       System.out.println(this.name + " is running.");
       Thread.sleep(100);
     } catch (Exception e) {
       e.printStackTrace();
     }
   }
 }

task-0 is running.
task-1 is running.

 import java.lang.reflect.Field;
 import java.util.concurrent.ArrayBlockingQueue;
 import java.util.concurrent.ThreadPoolExecutor;
 import java.util.concurrent.TimeUnit;
 import java.util.concurrent.ThreadPoolExecutor.DiscardOldestPolicy;
 
 public class DiscardOldestPolicyDemo {
 
   private static final int THREADS_SIZE = 1;
   private static final int CAPACITY = 1;
 
   public static void main(String[] args) throws Exception {
 
     // 创建线程池。线程池的"最大池大小"和"核心池大小"都为1(THREADS_SIZE)，"线程池"的阻塞队列容量为1(CAPACITY)。
     ThreadPoolExecutor pool = new ThreadPoolExecutor(THREADS_SIZE, THREADS_SIZE, 0, TimeUnit.SECONDS,
         new ArrayBlockingQueue<Runnable>(CAPACITY));
     // 设置线程池的拒绝策略为"DiscardOldestPolicy"
     pool.setRejectedExecutionHandler(new ThreadPoolExecutor.DiscardOldestPolicy());
 
     // 新建10个任务，并将它们添加到线程池中。
     for (int i = 0; i < 10; i++) {
       Runnable myrun = new MyRunnable("task-"+i);
       pool.execute(myrun);
     }
     // 关闭线程池
     pool.shutdown();
   }
 }
 
 class MyRunnable implements Runnable {
   private String name;
   public MyRunnable(String name) {
     this.name = name;
   }
   @Override
   public void run() {
     try {
       System.out.println(this.name + " is running.");
       Thread.sleep(200);
     } catch (Exception e) {
       e.printStackTrace();
     }
   }
 }

task-0 is running.
task-9 is running.

 import java.lang.reflect.Field;
 import java.util.concurrent.ArrayBlockingQueue;
 import java.util.concurrent.ThreadPoolExecutor;
 import java.util.concurrent.TimeUnit;
 import java.util.concurrent.ThreadPoolExecutor.AbortPolicy;
 import java.util.concurrent.RejectedExecutionException;
 
 public class AbortPolicyDemo {
 
   private static final int THREADS_SIZE = 1;
   private static final int CAPACITY = 1;
 
   public static void main(String[] args) throws Exception {
 
     // 创建线程池。线程池的"最大池大小"和"核心池大小"都为1(THREADS_SIZE)，"线程池"的阻塞队列容量为1(CAPACITY)。
     ThreadPoolExecutor pool = new ThreadPoolExecutor(THREADS_SIZE, THREADS_SIZE, 0, TimeUnit.SECONDS,
         new ArrayBlockingQueue<Runnable>(CAPACITY));
     // 设置线程池的拒绝策略为"抛出异常"
     pool.setRejectedExecutionHandler(new ThreadPoolExecutor.AbortPolicy());
 
     try {
 
       // 新建10个任务，并将它们添加到线程池中。
       for (int i = 0; i < 10; i++) {
         Runnable myrun = new MyRunnable("task-"+i);
         pool.execute(myrun);
       }
     } catch (RejectedExecutionException e) {
       e.printStackTrace();
       // 关闭线程池
       pool.shutdown();
     }
   }
 }
 
 class MyRunnable implements Runnable {
   private String name;
   public MyRunnable(String name) {
     this.name = name;
   }
   @Override
   public void run() {
     try {
       System.out.println(this.name + " is running.");
       Thread.sleep(200);
     } catch (Exception e) {
       e.printStackTrace();
     }
   }
 }

java.util.concurrent.RejectedExecutionException
  at java.util.concurrent.ThreadPoolExecutor$AbortPolicy.rejectedExecution(ThreadPoolExecutor.java:1774)
  at java.util.concurrent.ThreadPoolExecutor.reject(ThreadPoolExecutor.java:768)
  at java.util.concurrent.ThreadPoolExecutor.execute(ThreadPoolExecutor.java:656)
  at AbortPolicyDemo.main(AbortPolicyDemo.java:27)
task-0 is running.
task-1 is running.

 import java.lang.reflect.Field;
 import java.util.concurrent.ArrayBlockingQueue;
 import java.util.concurrent.ThreadPoolExecutor;
 import java.util.concurrent.TimeUnit;
 import java.util.concurrent.ThreadPoolExecutor.CallerRunsPolicy;
 
 public class CallerRunsPolicyDemo {
 
   private static final int THREADS_SIZE = 1;
   private static final int CAPACITY = 1;
 
   public static void main(String[] args) throws Exception {
 
     // 创建线程池。线程池的"最大池大小"和"核心池大小"都为1(THREADS_SIZE)，"线程池"的阻塞队列容量为1(CAPACITY)。
     ThreadPoolExecutor pool = new ThreadPoolExecutor(THREADS_SIZE, THREADS_SIZE, 0, TimeUnit.SECONDS,
         new ArrayBlockingQueue<Runnable>(CAPACITY));
     // 设置线程池的拒绝策略为"CallerRunsPolicy"
     pool.setRejectedExecutionHandler(new ThreadPoolExecutor.CallerRunsPolicy());
 
     // 新建10个任务，并将它们添加到线程池中。
     for (int i = 0; i < 10; i++) {
       Runnable myrun = new MyRunnable("task-"+i);
       pool.execute(myrun);
     }
 
     // 关闭线程池
     pool.shutdown();
   }
 }
 
 class MyRunnable implements Runnable {
   private String name;
   public MyRunnable(String name) {
     this.name = name;
   }
   @Override
   public void run() {
     try {
       System.out.println(this.name + " is running.");
       Thread.sleep(100);
     } catch (Exception e) {
       e.printStackTrace();
     }
   }
 }

task-2 is running.
task-3 is running.
task-4 is running.
task-5 is running.
task-6 is running.
task-7 is running.
task-8 is running.
task-9 is running.
task-0 is running.
task-1 is running.