JAVA并发，同步锁性能测试

测试主要从运行时间差来体现，数据量越大，时间差越明显，例子如下：

 package com.xt.thinks21_2;

 /**
  * 同步锁性能测试
  *
  * @author Administrator
  *
  */
 public class SynchronizedTimeTest {
     public volatile int inc = ;

     public void increase() {
         inc++;
     }

     public static void main(String[] args) {
         final SynchronizedTimeTest test = new SynchronizedTimeTest();
         for (int i = ; i < ; i++) {
             new Thread() {
                 public void run() {
                     for (int j = ; j < ; j++)
                         test.increase();
                 };
             }.start();
         }
         Long time1 = System.currentTimeMillis();
         while (Thread.activeCount() > ) {
             // 保证前面的线程都执行完
             Thread.yield();
         }
         Long time2 = System.currentTimeMillis();
         System.out.println("time1:" + time1 + " time2:" + time2);
         Long timeDiff = time2 - time1;
         System.out.println("time:" + timeDiff + "-->" + test.inc);
     }
 }

上面是方法未加synchronized运行结果：

time1:1429805281187 time2:1429805281187
time:0-->75809

方法添加synchronized运行结果：

time1:1429805416628 time2:1429805416645
time:17-->100000