using System;

public class Program

{

    public static void Main()

    {

        var a = new A();

        a.Do1(); //deadlock?        

        Console.WriteLine("Hello World");   

    }

    public class A

    {

        private Object _locker = new Object();

        public void Do1()

        {

            lock(_locker)

            {

                Do2();

            }

        }

        public void Do2()

        {

            lock(_locker)

            {

                Do3();

            }

        }

        public void Do3()

        {

            //....

        }       

    }

    public class B

    {

        private int _locker = 234;

        public void Do1()

        {

            lock((object)_locker)

            {

                //do somethoing;

            }

        }

    }           

}