关于多线程的问题
麻烦大家看一下下边的程序片断的输出为什么是
in thread 2 maple
in thread 1 maple
我在两个线程里都用sychronized把a锁掉了阿，为什么会出现并发访问的问题，难道sleep()会释放对象锁？？
public class ThreadTest {
static String a = " ";
public static void main(String[] args) {
Thread thread1 = new Thread() {
public void run() {
synchronized (a) {
a = "lincoln ";
try {
Thread.sleep(500);
} catch (InterruptedException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
System.out.println( "in thread 1 " + a);
}
}
};
Thread thread2 = new Thread() {
public void run() {
synchronized (a) {
a = "maple ";
try {
Thread.sleep(100);
} catch (InterruptedException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
System.out.println( "in thread 2 " + a);
}
}
};
thread1.start();
thread2.start();
}
}
[解决办法]
和你的一摸一样啊
public class ThreadTest {
static String a = " ";
public static void main(String[] args) {
Thread thread1 = new Thread() {
public void run() {
synchronized ( " ") {
a = "lincoln ";
try {
Thread.sleep(500);
} catch (InterruptedException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
System.out.println( "in thread 1 " + a);
}
}
};
Thread thread2 = new Thread() {
public void run() {
synchronized ( " ") {
a = "maple ";
try {
Thread.sleep(100);
} catch (InterruptedException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
System.out.println( "in thread 2 " + a);
}
}
};
thread1.start();
thread2.start();
}
}
