Java提供了synchronized关键字用于修饰方法，使用synchronized修饰的方法被称为同步方法。当然，synchronized关键字除了修饰方法之外，还可以修饰普通代码块，使用synchronized修饰的代码块被称为同步代码块。
Java语法规定，任何线程进入同步方法，同步代码块之前，必须先获取同步方法，同步代码块对应的同步监控器。
对于同步代码块而言，程序必须显式为它指定同步监视器；对于同步非静态方法而言，该方法的同步监视器是this 即调用该方法的Java对象；对于静态的同步方法而言，该方法的同步监视器不是this，而是该类本身。
public class SynchronizedStatic implements Runnable{
static boolean staticFlag = true;
public static synchronized void test0(){
for(int i=0;i<100;i++){
System.out.println("test0:"+Thread.currentThread().getName()+""+i);
}
}
public void test1(){
synchronized(this){
for(int i=0;i<100;i++){
System.out.println("test1:"+Thread.currentThread().getName()+""+i);
}
}
}
@Override
public void run() {
// TODO Auto-generated method stub
if(staticFlag){
staticFlag=false;
test0();
}else{
staticFlag=true;
test1();
}
}
public static void main(String[] args) throws Exception{
SynchronizedStatic ss = new SynchronizedStatic();
new Thread(ss).start();
//Thread.sleep(10);
new Thread(ss).start();
}
}
test0:Thread-00
test1:Thread-10
test1:Thread-11
test1:Thread-12
test1:Thread-13
test1:Thread-14
test1:Thread-15
test0:Thread-01
test0:Thread-02
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test1:Thread-18
test0:Thread-04
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test0:Thread-08
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test0:Thread-035
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test0:Thread-036
test1:Thread-168
test0:Thread-0