java两个线程互相守护

dota打累了写个小demo
最近由于工作需要，需要实现一个线程无论任何情况下都不能挂掉，就算挂掉了也必须继续运行该线程里的功能，想了一下其实也非常简单，无非就是两个线程互相守护，两个线程里实现同样的功能，线程A挂了启动线程B，线程B挂了启动线程A，好了废话不多说，直接上代码：

package com.thread.daemon.test;

import java.util.ArrayList;
import java.util.List;

/**
* 两个线程互相守护，线程A挂了启动线程B，线程B挂了启动线程A
* @author liangjian
*/
public class ThreadDaemonTest {

static List<String> list = new ArrayList<>();
static Thread threadA ;
static Thread threadB ;

public static void threadDaemonA(){
threadA = new Thread(new Runnable() {
boolean flag = true;
int count = 0;
@Override
public void run() {
threadA.setName("threadDaemonA ");
while(flag){
try {
threadA.sleep(1000);
} catch (InterruptedException e1) {
e1.printStackTrace();
flag = false;
Thread.currentThread().interrupt();
threadA = null;
threadDaemonB();
}finally{
}
count++;
System.out.println(threadA.getName()+count+ " <--> threadB = "+threadB);
if(count == 10){
System.err.println(count);
try {
String temp = list.get(0);
} catch (Exception e) {
e.printStackTrace();
threadDaemonB();
flag = false;
Thread.currentThread().interrupt();
threadA = null;
return;
}finally{
}
}
}
}
});
threadA.start();
}
public static void threadDaemonB(){
threadB = new Thread(new Runnable() {
boolean flag = true;
int count = 0;
@Override
public void run() {
threadB.setName("threadDaemonB ");
while(flag){
try {
threadB.sleep(1000);
} catch (InterruptedException e1) {
e1.printStackTrace();
flag = false;
Thread.currentThread().interrupt();
threadB = null;
threadDaemonA();
}
count++;
System.out.println(threadB.getName()+count+" <--> threadA = "+threadA);
if(count == 10){

try {
String temp = list.get(0);
return ;
} catch (Exception e) {
e.printStackTrace();
flag = false;
threadB = null;
Thread.currentThread().interrupt();
threadDaemonA();
}finally{
}
}
}
}
});
threadB.start();
}

public static void main(String[] args) {
threadDaemonA();
}

}