Question

As far as my understanding is so far; a class which implements runnable seems to only be able to perform one set task within its run method. How is it possible to create a new thread and then run different methods from this one additional thread, without needing to create some new runnable class for every set task.

Answer 1

Your Runnable class can call any logic it likes. The logic you want to run must be in some class, could be different methods of the Runnable class or could be in lots of other classes.

How did you plan to tell the runnable what to do?

You could do something like:

 MyRunnable implements Runnable {
     private String m_whatToDo;

     public MyRunnable(String whatToDo) {
           m_whatToDo = whatToDo;
     }


     public void Runnable run() {
          if ("x".equals(m_whatToDo) {
                 // code to do X
          } else if ( "y".equals(m_whatToDo) {
                 // code to do Y
          } else {
                 // some error handling
          }
     }
 }

Or as Srikanth says you could communicate the intent by other means such as thread names.

However I don’t see much overhead in creating a runnable class. Just adding a public void run() to a class is surely not that big a deal?