public ThreadPoolExecutor(int corePoolSize,
                          int maximumPoolSize,
                          long keepAliveTime,
                          TimeUnit unit,
                          BlockingQueue<Runnable> workQueue,
                          ThreadFactory threadFactory,
                          RejectedExecutionHandler handler) {

import java.util.concurrent.ArrayBlockingQueue;
import java.util.concurrent.ThreadPoolExecutor;
import java.util.concurrent.TimeUnit;public class DiscardPolicyDemo {private static final int THREADS_SIZE = 2;private static final int MAX_MUM_POOLSIZE = 4;private static final int CAPACITY = 2;public static void main(String[] args) throws Exception {// 创建线程池。ThreadPoolExecutor pool = new ThreadPoolExecutor(THREADS_SIZE, MAX_MUM_POOLSIZE, 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;}public void run() {try {System.out.println(this.name + " is running.");Thread.sleep(100);} catch (Exception e) {e.printStackTrace();}}
}

输出：

task-1 is running.
task-4 is running.
task-0 is running.
task-5 is running.
task-2 is running.
task-3 is running.

import java.util.concurrent.ArrayBlockingQueue;
import java.util.concurrent.ThreadPoolExecutor;
import java.util.concurrent.TimeUnit;public class DiscardOldestPolicyDemo {private static final int THREADS_SIZE = 2;private static final int MAX_MUM_POOLSIZE = 3;private static final int CAPACITY = 3;public static void main(String[] args) throws Exception {// 创建线程池。ThreadPoolExecutor pool = new ThreadPoolExecutor(THREADS_SIZE, MAX_MUM_POOLSIZE, 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;}public void run() {try {System.out.println(this.name + " is running.");Thread.sleep(200);} catch (Exception e) {e.printStackTrace();}}
}

输出结果：

task-0 is running.
task-1 is running.
task-5 is running.
task-7 is running.
task-8 is running.
task-9 is running.

import java.util.concurrent.ArrayBlockingQueue;
import java.util.concurrent.RejectedExecutionException;
import java.util.concurrent.ThreadPoolExecutor;
import java.util.concurrent.TimeUnit;public class AbortPolicyDemo {private static final int THREADS_SIZE = 2;private static final int MAX_MUM_POOLSIZE = 4;private static final int CAPACITY = 2;public static void main(String[] args) throws Exception {// 创建线程池。ThreadPoolExecutor pool = new ThreadPoolExecutor(THREADS_SIZE, MAX_MUM_POOLSIZE, 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;}public void run() {try {System.out.println(this.name + " is running.");Thread.sleep(200);} catch (Exception e) {e.printStackTrace();}}
}

输出结果：

task-0 is running.
task-1 is running.
task-4 is running.
task-5 is running.
java.util.concurrent.RejectedExecutionException: Task thread.MyRunnable@5e2de80c rejected from java.util.concurrent.ThreadPoolExecutor@1d44bcfa[Running, pool size = 4, active threads = 4, queued tasks = 2, completed tasks = 0]
    at java.util.concurrent.ThreadPoolExecutor$AbortPolicy.rejectedExecution(ThreadPoolExecutor.java:2063)
    at java.util.concurrent.ThreadPoolExecutor.reject(ThreadPoolExecutor.java:830)
    at java.util.concurrent.ThreadPoolExecutor.execute(ThreadPoolExecutor.java:1379)
    at thread.AbortPolicyDemo.main(AbortPolicyDemo.java:27)
task-2 is running.
task-3 is running.

import java.util.concurrent.ArrayBlockingQueue;
import java.util.concurrent.ThreadPoolExecutor;
import java.util.concurrent.TimeUnit;public class CallerRunsPolicyDemo {private static final int THREADS_SIZE = 2;private static final int MAX_MUM_POOLSIZE = 4;private static final int CAPACITY = 2;public static void main(String[] args) throws Exception {// 创建线程池。ThreadPoolExecutor pool = new ThreadPoolExecutor(THREADS_SIZE, MAX_MUM_POOLSIZE, 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;}public void run() {try {System.out.println(this.name + " is running.");Thread.sleep(100);} catch (Exception e) {e.printStackTrace();}}
}

输出结果：

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