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");
				}
			}
		}
	}
}

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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)).