Chapter 4: Implementing Runnable Versus Extending Thread

	Chapter 4 - Implementing Runnable Versus Extending Thread
	Java Thread Programming
	Paul Hyde

Copyright 1999 Sams Publishing

---

Interface java.lang.Runnable

Rather than inherit from Thread , a class can implement the interface java.lang.Runnable to allow a thread to be run within it. Runnable specifies that only one method be implemented:

public void run()

This is the same method signature that run() has in Thread . In fact, Thread also implements Runnable ! Note that run() does not take any parameters, does not return anything, and does not declare that it throws any exceptions.

The Runnable interface can be used to get around the lack of multiple inheritance. Figure 4.5 shows SecondCounter extending JComponent and implementing Runnable . SecondCounter

IS-A Component and can be added to containers. SecondCounter also IS-A Runnable and can have a new thread begin execution with its run() method.

Figure 4.5: Getting around the multiple inheritance problem with Runnable.

Toc