In this article, we will examine the subtleties of using newly introduced Lock classes in java.util.concurrent.locks package and their advantages over traditional "synchronized" blocks and methods.

In this article we will discuss how to use the new interface Callable introduced in java.concurrent.util in Java 5. Callable along with another interface Future allows us to obtain a return value from a method executed in a separate thread.
In the second example we will also examine the usage of FutureTask, an implementation of Future.

In an earlier article on Executor, we looked at how we can create use the executor to create thread pools to manage our multi-threaded program. We shall continue to explore additional features of this class.
Here we will extend the ThreadPooledExecutor class and provide our implementation to replace the empty implementation.