这个多线程Java代码如何工作？

class Account {
        private Integer number = 0;
        public synchronized void setNumber(Integer number) {
            this.number = number;
        }

         public synchronized Integer getNumber() {
            return number;
        }
    }

    class Client extends Thread {
        Account account;
        public Client(Account account) {
            this.account = account;
        }
        public  void run() {
            for (int i = 1; i <= 1000; i++) {
            account.setNumber(account.getNumber() + 1);
             }
        }
    }

    public class Run {
        public static void main(String[] args) throws Exception {
            Account account = new Account();
            Client one = new Client(account);
            Client two = new Client(account);
            one.start();
            two.start();
            one.join();
            two.join();
           System.out.println("Exiting main");
       System.out.println("account number value: " +account.getNumber());        
        }
    }

主方法完成时,数字的值是多少？是2000还是不到2000？我得到的不到2000.两个线程如何同时从run()调用getNumer()或setNumber(),因为每个线程都是同步的？