Q1:

public class MyRunnable implements Runnable 
{
    public void run() 
    {
        // some code here
    }
}

which of these will create and start this thread?

ANS:A - new Runnable(MyRunnable).start();

Because the class implements Runnable, an instance of it has to be passed to the Thread constructor, and then the instance of the Thread has to be started. A is incorrect. There is no constructor like this for Runnable because Runnable is an interface, and it is illegal to pass a class or interface name to any constructor. B is incorrect for the same reason; you can't pass a class or interface name to any constructor. D is incorrect because MyRunnable doesn't have a start() method, and the only start() method that can start a thread of execution is the start() in the Thread class.