我发现许多地方提及synchronized的关键字不能被继承,但是通过实验发现synchronized的关键字是能够被继承的,是我的实验方式不对?请高手指教,谢谢
import java.text.SimpleDateFormat;
import java.util.Date;
public class TestMain {
/**
* @param args
*/
public static void main(String[] args) {
// TODO Auto-generated method stub
UtilChild util = new UtilChild();
AThread aThread1 = new AThread(util,1);
aThread1.start();
AThread aThread2 = new AThread(util,2);
aThread2.start();
AThread aThread3 = new AThread(util,3);
aThread3.start();
AThread aThread4 = new AThread(util,4);
aThread4.start();
AThread aThread5 = new AThread(util,5);
aThread5.start();
}
}
class Util{
public static synchronized void test1(int i){
System.out.println(getDetailDate() + " test1(i), i: " + i);
try {
Thread.sleep(5000);
} catch (InterruptedException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
System.out.println(getDetailDate() + " test1(i), i: " + i);
}
public static synchronized void test2(int i){
System.out.println(getDetailDate() + " test2(i), i: " + i);
}
public static void test3(int i){
System.out.println(getDetailDate() + " test3(i), i: " + i);
}
public synchronized void test4(int i){
System.out.println(getDetailDate() + " test4(i), i: " + i);
try {
Thread.sleep(5000);
} catch (InterruptedException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
System.out.println(getDetailDate() + " test4(i), i: " + i);
}
public synchronized void test5(int i){
System.out.println(getDetailDate() + " test5(i), i: " + i);
}
public static String getDetailDate() {
SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
return sdf.format(new Date());
}
}
class UtilChild extends Util{
}
class AThread extends Thread{
UtilChild util = null;
int i = 1;
public AThread(UtilChild util, int i){
this.util = util;
this.i = i;
}
public void run(){
if(this.i== 1){
util.test1(1);
}else if(this.i== 2){
util.test2(2);
}else if(this.i== 3){
util.test3(i);
}else if(this.i== 4){
util.test4(i);
}else if(this.i== 5){
util.test5(i);
}
}
}
运行结果:
2012-03-30 00:40:02 test4(i), i: 4
2012-03-30 00:40:02 test3(i), i: 3
2012-03-30 00:40:02 test1(i), i: 1
2012-03-30 00:40:07 test4(i), i: 4
2012-03-30 00:40:07 test5(i), i: 5
2012-03-30 00:40:07 test1(i), i: 1
2012-03-30 00:40:07 test2(i), i: 2
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