java并发编程的艺术（1）并发编程的挑战

package 并发编程01.串行和并发的效率比较;
public class ConcurrencyTest {
    private static final long count=100000000l;
    public static void concurrency() throws InterruptedException {
        long begin=System.currentTimeMillis();
        Thread thread= new Thread(new Runnable(){
                @Override
                public void run() {
                    for(int i=0;i<count;i++){
                    }
                }
            });
        thread.start();
        long end=System.currentTimeMillis();
        thread.join();
        System.out.println("并发消耗时间为："+(end-begin));
    }
    public static void serial(){
        long begin=System.currentTimeMillis();
        for(int i=0;i<count;i++){
        }
        long end=System.currentTimeMillis();
        System.out.println("串行消耗时间为："+(end-begin));
    }
    public static void main(String[] args) throws InterruptedException {
        concurrency();
        serial();
    }
}
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package 并发编程01.死锁的案例;
import java.awt.*;
/*
*
* @author idea
* @date 2018/7/13
* @des 模拟在多线程编程里面出现的死锁情况
* 这一段代码的主要功能就在于让t1,t2两个线程互相抢占对方的资源，导致双方都没办法获取到相应的锁
*/
public class DeadLock {
    public String locka="a";
    public String lockb="b";
    public static void main(String[] args) {
        new DeadLock().deadLock();
    }
    public void deadLock(){
        Thread t1=new Thread(new Runnable() {
            @Override
            public void run() {
                synchronized (locka){
                    try {
                        Thread.sleep(100);
                    } catch (InterruptedException e) {
                        e.printStackTrace();
                    }
                    synchronized (lockb){
                        System.out.println("this is a");
                    }
                }
            }
        });
        Thread t2=new Thread(new Runnable() {
            @Override
            public void run() {
                synchronized (lockb){
                    synchronized (locka){
                        System.out.println("this is b");
                    }
                }
            }
        });
        t1.start();
        t2.start();
    }
}
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