Which of these keywords are used to implement synchronization?

class newthread extends Thread
{
Thread t;
String name;
newthread(String threadname)
    {
  name = threadname;
  t = new Thread(this,name);
  t.start();
}
public void run()
    {
    }

}
class multithreaded_programing
{
    public static void main(String args[])
    {
  newthread obj1 = 	 new newthread("one");
  newthread obj2 =	 new newthread("two");
        try
        {
            obj1.t.wait();	
            System.out.print(obj1.t.isAlive());
        }
        catch(Exception e)
        {
  System.out.print("Main thread interrupted");
        }
    }
}