From the docs

public void start()

   Causes this thread to begin execution; the Java Virtual Machine
calls the run method of this thread.

   The result is that two threads are running concurrently: the current
thread (which returns from the call to the start method) and the other
thread (which executes its run method).

   It is never legal to start a thread more than once. In particular, a
thread may not be restarted once it has completed execution.

   Throws:
       IllegalThreadStateException - if the thread was already started.
   See Also:
       run(), stop()

Subclassing Thread: bad

Implementing Runnable and creating a separate Thread to start it: good

The underlying operating-system, platform-specific thread used by the
Thread object is dead after one usage and can't be resurrected.

For the rest of your question: Rework them to make sense.

There is only one way to create a Thread, and that's by calling one of
the overloads of new Thread(...). There are two ways of *providing the
Runnable code that the thread will execute*: extending Thread, or
implementing a Runnable and supplying it to the Thread's constructor.
Orthogonality concerns suggest that the latter is generally the
preferable approach.