java线程死锁例子

public class DealLockTest implements Runnable {
static String i = new String();
static String j = new String();
private String str = null;
public DealLockTest(String str) {
this.str = str;
}
public static void main(String[] args) {
new Thread(new DealLockTest("i")).start();
new Thread(new DealLockTest("j")).start();
}
public void run() {
if (str.equals("i")) {
synchronized (i) {
System.out.println(Thread.currentThread().getName()+":"+"i");
Thread.yield();
synchronized (j) {
System.out.println("i is over");
}
}
} else {
synchronized (j) {
System.out.println(Thread.currentThread().getName()+":"+"j");
Thread.yield();
synchronized (i) {
System.out.println("j is over");
}
}
}
}
}

线程何时发生死锁呢?
最简单的情况是当1个线程获得了资源A,当它再获得资源B时,就可以完成任务.而在它获得了A的时候
另一个线程获得了资源B,去抢资源A..此时,就发生了死锁
前提(共享资源(static),加锁(synchronized)).