Question

java产生死锁原因，代码如下。

package demo;
class Resource2 {
private String name;
private int count = 1;
private boolean flag = false;

public synchronized void set(String name) {
if (flag)
try {
wait();
} catch (InterruptedException e) {
System.out.println(e);
}

this.name = name;

count++;
flag = true;
notify();
}
public synchronized void out() {
if (flag)
try {
wait();
} catch (InterruptedException e) {
System.out.println(e);
}
System.out.println(Thread.currentThread().getName() + "\tname:" + name);
flag = false;
notify();
}
}
class Producer implements Runnable {
private Resource2 r;
public Producer(Resource2 r) {
super();
this.r = r;
}
public void run() {
while (true) {
r.set("小苍");
}
}
}
class Consumer implements Runnable {
Resource2 r;
public Consumer(Resource2 r) {
super();
this.r = r;
}
public void run() {
while (true) {
r.out();
}
}
}
public class ProducerConsumer {
public static void main(String[] args) {
Resource2 r = new Resource2();
Producer p = new Producer(r);
Consumer c = new Consumer(r);
Thread t1 = new Thread(p);
Thread t2 = new Thread(c);
t1.start();
t2.start();
}
}

Answer 1

你这个不是死锁，就是flag的判断有问题，每个线程都是自己把自己锁住了，当flag为true时，看以下两段代码：
public synchronized void set(String name) {
if (flag)
try {
wait();

public synchronized void out() {
if (flag)
try {
wait();

两个线程都在wait，当然卡住不动了。

看你的代码，把set那段改成这样应该就好了：
public synchronized void set(String name) {
if (!flag)
try {
wait();