The emergence of the robotics industry

The leader of the PC revolution predicts that the next hot field will be robotics. By Bill Gates. Scientific American. "[T]he emergence of the robotics industry, which is developing in much the same way that the computer business did 30 years ago. ...

Cybernetics

"The science of control and communication in the animal and the machine"
Norbert Wiener

What Comes After Web 2.0?

Many researchers and entrepreneurs are working on Internet-based knowledge-organizing technologies that stretch traditional definitions of the Web. Lately, some have been calling the technologies "Web 3.0." But really, they're closer to "Web 2.1."

Typically, the name Web 2.0 is used by computer programmers to refer to a combination of a) improved communication between people via social-networking technologies, b) improved communication between separate software applications--read "mashups"--via open Web standards for describing and accessing data, and c) improved Web interfaces that mimic the real-time responsiveness of desktop applications within a browser window.

To see how these ideas may evolve, and what may emerge after Web 2.0, one need only look to groups such as MIT's Computer Science and Artificial Intelligence Laboratory, the World Wide Web Consortium, Amazon.com, and Google. All of these organizations are working for a smarter Web, and some of their prototype implementations are available on the Web for anyone to try. Many of these projects emphasize leveraging the human intelligence already embedded in the Web in the form of data, metadata, and links between data nodes. Others aim to recruit live humans and apply their intelligence to tasks computers can't handle. But none are ready for prime time.

GETTING TO KNOW SYNCHRONIZERS

Support for synchronization has been part of the Java programming language since the initial release of the Java platform. This support is designed to prevent simultaneous access to critical code blocks and shared variables. Synchronization gives you the choice of adding the synchronized keyword to a method or wrapping a code section in a synchronized block. J2SE 5.0 adds several mechanisms for coordinating between different threads in an application. This added support is provided by the new java.util.concurrent package. The package includes classes that offer semaphores, barriers, latches, and exchangers -- this tip looks at each of these in more detail.

Concurrent Programming with J2SE 5.0

Java is a multithreaded programming language that makes programming with threads easier, by providing built-in language support for threads. The built-in primitives however, such as synchronized blocks, Object.wait(), and Object.notify() are insufficient for many programming tasks. This leads developers to implement their own high-level synchronization facilities, but given the difficulty of concurrency issues, their implementations may not be correct, efficient, or high quality.

The Java 2 Platform, Standard Edition release 5.0 (J2SE 5.0), which is also known as Tiger, has provided a new path to multithreading in the Java programming language. The original mechanisms for coordinating threads with wait() and notify() are now enhanced with new and sophisticated mechanisms for working with threads. The new mechanisms are part of the java.util.concurrent package, which aims to offer a standard set of concurrency utilities that will ease the task of developing multithreaded applications and servers. In addition, such standards will improve the quality of such applications. The package has been defined through the Java Community Process as JSR 166: Concurrency Utilities.

This article provides an overview and an introductory tutorial to the new concurrency mechanisms that have been added to J2SE 5.0. It helps developers get started using the new java.util.concurrent package and its subpackages.