Java 死锁的造成

1. java 的死锁有点像相对而行走在独木桥的人，占用当前资源，又等待着另一个资源，并且是多个任务互相占用；
   代码案例：

public static void main(String[] args) {
    final Object a = new Object();
    final Object b = new Object();
    Thread threadA = new Thread(new Runnable() {
        public void run() {
            synchronized (a) {
                try {
                    System.out.println("now i in threadA-locka");
                    Thread.sleep(1000l);
                    synchronized (b) {
                        System.out.println("now i in threadA-lockb");
                    }
                } catch (Exception e) {
                    // ignore
                }
            }
        }
    });

    Thread threadB = new Thread(new Runnable() {
        public void run() {
            synchronized (b) {
                try {
                    System.out.println("1");
                    Thread.sleep(1000l);
                    synchronized (a) {
                        System.out.println("2");
                    }
                } catch (Exception e) {
                    // ignore
                }
            }
        }
    });

    threadA.start();
    threadB.start();
}

如果想要解决相关死锁的问题：
1 顺序执行
2 多个对象资源占用
3 lock 释放资源