死鎖的實現
死鎖:就是當程式拿著鎖A的時候再想拿鎖B去做一些事情,在沒拿到鎖B之前這個鎖B被另外一個執行緒拿去了,另外一個執行緒拿到B再想拿鎖A去做事情。但是執行緒1沒有釋放鎖A,所以執行緒2一直不能繼續做事情,就釋放不了鎖B導致執行緒1也無法繼續進行下面的事情。所以形成了死鎖。
死鎖必須是多執行緒的。
public class DealLockDemo implements Runnable{
private boolean flag ;
private static final Object locka = new Object();
private static final Object lockb = new Object();
public DealLockDemo(boolean flag){
this.flag = flag;
}
@Override
public void run() {
// TODO Auto-generated method stub
if(flag){
synchronized(locka)
{
System.out.println(Thread.currentThread().getName()+" .. if locka");
synchronized(lockb){
System.out.println(Thread.currentThread().getName()+".. if lockb");
}
}
}else{
synchronized(lockb){
System.out.println(Thread.currentThread().getName()+".. else lockb");
synchronized (locka) {
System.out.println(Thread.currentThread().getName() + ".. else locka");
}
}
}
}
}
這個是呼叫類:
public class RunDealLock {
public static void main(String[] args) {
DealLockDemo dealLockDemo = new DealLockDemo(true);
DealLockDemo dealLockDemo2 = new DealLockDemo(false);
Thread thread = new Thread(dealLockDemo);
Thread thread2 = new Thread(dealLockDemo2);
thread.start();
thread2.start();
}
}