So you want to build a robot that walks around and bumps into things. But that's not enough for you (this is the year 2000, after all); you also want to control your robot over the Internet. What's more, you want to use Java to control it.

It began sometime in late '96 or early '97 ­ JDK 1.0 still ruled and Tandem was still called Tandem, not Digital or Compaq ­ when people from IBM, Tandem and Oracle met and started to muse.

Before we start on the technical front, let me tell you about my latest acquisition. I recently went out to purchase a watch. My wife wanted me to buy one of the fancy ones, but I'm more excited by watches that have all the features ­ stopwatch, backlight, barometer, altimeter, everymeter ­ and the time displayed in BOLD DIGITAL NUMBERS. I usually end up using maybe three out of a hundred features, but at least I have them.

One unfortunate aspect of the many enterprise APIs and specifications that Sun has released over the last few years has been the lack of information about how some of these APIs interact with one another. In particular, two very useful specifications ­ the Java Messaging Service (JMS) and Enterprise JavaBeans (EJB) ­ have been released and already implemented individually by many application server vendors. What wasn't considered in this process, at least at this stage, is how the two would (or should) work together. Enterprise JavaBeans is a server-side component architecture, which provides remote, distributed, secure objects with built-in transaction support. JMS is a portable messaging service architecture and API that provides for persistent, point-to-point or publish/subscribe messaging with transaction support.

Developers at some point in their careers will find themselves standing at the whiteboard, trying their best to regurgitate some complex development design they've spent all night working on. This is usually done with a series of strange symbols, arrows and scribblings in an attempt to convey the clarity that may lie in the head of said developer (unless of course he or she doesn't know what exactly the design is supposed to look like). Either way, you have the same problem.

A common set of programming problems drove us to develop a Java class we call PropArgs. Consider the following questions a programmer may want answered about a program: Which RDBMS instance should data come from? Does this particular user have any personal preferences I should be setting? Should debugging code be executed during a particular run of a program? Are there different execution paths based on the current operating system? Should the programmer be operating in batch or interactive mode? What directory should disk output be written to?

Most Web-based applications today confine users to the frame of their browser, restricting them to viewing only one Web page at a time. Technologies such as JavaScript make additional browser windows possible, but this approach doesn't enable the kind of customized menus, toolbars and windowing features available in a traditional client/server application. Java Swing provides additional capabilities such as the ability to create windows outside the browser that have the look and feel of a traditional client application. The techniques described in this article can be used to migrate traditional client/server applications to a Web-based environment.

Say you're writing an Enterprise JavaBean that represents a persistent object, such as a customer or a product. You have two choices for getting data (such as customer name and product number) from the bean to the database and back:

Part 4 of a series discussing the many languages that compile and/or run on the Java platform

Twenty years after it first made waves, rule-based technology is making a comeback. Java developers with an eye on the e-commerce market are becoming aware of how integrating business rules and objects in Java can help expand Java into new niches within Web-based applications. This article discusses how rules fit with Java, the types of rule engines available and how a rule engine is used to execute rules for integration into a Java applet or application.

XML has become the standard format for B2B data exchange. To actually implement such exchanges, however, the programmer must provide data transport and translation services. Java-based messaging provides an ideal transport for XML. This article explores how to use a Java messaging server as the infrastructure for exchanging XML data between B2B participants.

If you know SQL and Java, and you want to learn SQLJ, this series of articles is for you! I'm going to introduce SQLJ, the standard for embedding database SQL statements in Java programs. You may be familiar with JDBC, an API for talking SQL with the database. SQLJ takes many ideas from JDBC further by providing a language interface for SQL statements in Java. This allows programmers to concentrate on what to say, not how to say it.

With the proliferation of Java-based application servers at the core of today's Web applications, the preferred Web architecture that has emerged places Java in the middle tier, gathering data from myriad sources, and HTML presenting that data through a Web browser.

This article is Part 3 of an interactive series that discusses the many languages that compile and/or run on the Java platform. Java Developer's Journal invites you to vote for your favorite non-Java programming language in the JDJ forum. Your vote will decide which languages will be covered by the series, and in what order. A lot of languages work in the JVM, but this series will cover only the most popular, as determined by your votes.

They're one of the most commonly used computing tools in business today, regardless of a company's revenues or number of employees. Wall Street money mavens use them, and so does your hometown accountant...spreadsheets . Did you ever tweak spreadsheet formulas to play "what-if" games with your stock portfolio? Have you ever received an e-mail with a spreadsheet attachment full of sales figures or forecasts? And by the way, how did your friend send you the results of this week's fantasy football league?

EJB servers are transactional servers that allow developers to concentrate on business logic. The EJB model implements two-phase commits, transaction context propagation and distributed transaction, although it's up to the vendors to decide which technique to use. A transaction is formally defined as an "ACID" (atomic, consistent, isolated, durable) unit of work.

As a consultant, developer and database administrator, I've often been asked to provide coding guidelines and tuning assistance for Java code that utilizes JDBC. Over time, I've been introduced to or developed standard coding practices that make JDBC code faster and less error-prone, and easier to read, understand and use. This article documents some of the more important "best practices" for using JDBC libraries to perform database access. As most of my clients are using Oracle database technologies, I've included several practices that are Oracle-specific.

In this article we're going to describe a tool that we've created to help OO newcomers understand the class/instance relationship, inheritance between classes and linking between objects...by automatically converting an object graph into HTML. The tool we've created is based on the "circlegram" idea used by almost every object-oriented teacher during conventional "chalk and blackboard" lessons.

Several folks in the computing industry think of 1999 as having been the "Year of the Application Server." But while the term application server itself may be a fairly recent addition to the software computing vocabulary, the application server market has already become one of the fastest-growing markets in n-tier computing. Business analysts estimate its value as being likely to reach the multibillion-dollar level in 2001.

Java programmers have been anxiously awaiting the release of the Java Media Framework 2.0 for more than a year. Not only does JMF 2.0 finally let you capture audio and video content, but it claims to solve the most irritating limitations of the JMF 1.x release. Does JMF 2.0 live up to its hype? This article explores the new features and reveals whether this release was worth the wait.

Exception chaining (also known as 'nesting exceptions'), is a technique for handling exceptions. A list is built of all the exceptions thrown as a result of a single originating exception as it's converted from lower to higher levels of abstraction. It can be used in both client and server environments to greatly simplify software debugging without adding undue complexity. This article discusses good exception-handling techniques and shows how to implement and use exception chaining.

The use of Java in Web browsers has had mixed results. Applications that run in browsers rather than locally find a host of different hurdles. They're more restricted, run slower at times and take a long time to load, thus making complex applications more difficult. Advances in security and virtual machine technology have addressed the first two items. The third item remains somewhat challenging. Faster modems, increased bandwidth and compressed file formats alleviate the problem somewhat but their impact varies. When fourth-generation browsers appeared, they included some new technology with features that allowed developers to have their applets and supporting classes installed permanently.

What This Series Is About. This article is Part 2 of a series that discusses the many languages that compile and/or run on the Java platform. This is an interactive series. Java Developer's Journal invites you to vote for your favorite non-Java programming language in the JDJ Forum. Your vote will decide which languages will be covered by the series, and in what order. The last time I checked, JPython and NetRexx were neck and neck. NetRexx, though not mentioned previously, will be covered in the next article.

The Java servlet API specifies a very lightweight framework for developing Web applications. Although servlet technology is just one of the building blocks in the J2EE architecture, developers often use servlets to build full-fledged Web applications. Today several vendors and organizations provide servers and containers that implement the servlet API. For an overview of the servlet programming model, and some of the advanced features of Java servlets, refer to Part 1 of this article (JDJ, Vol. 5, issue 2).

Enterprise JavaBeans are being promoted as the component architecture for the new decade. The word Enterprise in the name would imply that EJBs are to the server environments what JavaBeans are to client computing. Both are component models, both are for Java, both try to deliver on the promise "write once, run anywhere." Beyond that, however, there is little commonality between them. EJB is not actually a software product but rather a specification of a server-side component architecture, to be implemented by vendors of server software. The specification combines object distribution with transaction processing and persistence. Its goal is to provide a standard architecture for building scalable, portable and distributed enterprise systems.

RTP and RTSP: Protocols that address the transportation of multimedia content over IP. The Internet is strewn with multimedia minefields. Lost or out-of-sequence packets and transmission delays can create havoc in your applications. Fortunately, you can overcome these problems by using protocols optimized for multimedia transportation. This article explains why these protocols are necessary, and examines how the JMF implements them and how you can use them to spice up your programs.

With the release of the Java 2 Platform, Enterprise Edition, Java-based Web application servers are gaining in popularity. Although application servers have been around for a few years, they forced programmers to be tied to a proprietary API. Support of J2EE by application server vendors standardizes the API we write to, easing training, staffing and support costs. Perhaps most important in our dynamic Web vendor environment, writing code to an industry standard reduces the huge risk a customer takes in choosing a particular vendor should that vendor disappear.

A tip window (also known as a tool tip window) is a small popup window that displays a single line of descriptive text. Tip windows are usually displayed over toolbar buttons to provide textual help about a toolbar button's functionality. The tip window control is available for Swing components via the JComponent class's setToolTipText() method; unfortunately, the AWT doesn't have an equivalent control at its disposal. This article details the classes that constitute my implementation of an AWT tip window control.

The multimedia objects in Sun's Java Development Kits are so primitive that they're worthless for serious development. Fortunately, Sun has overhauled Java's multimedia capabilities with the release of the Java Media Framework. In this article I'll explain why the JMF architecture is a significant improvement and show you how to use these objects in your applets or applications.

Back before Java became popular, I was a C++ bigot. I programmed in nothing but C++. I lived, ate and breathed C++. If it wasn't C++, it was rubbish. I thought C++ was the alpha and omega of object-oriented programming. I had "operator overloading" for breakfast, "templates" for lunch and "multiple inheritance" for dinner, and I always went back for seconds.

In the last couple of years Sun has introduced a number of APIs targeted toward enterprise application development. One of the most exciting of these is the Java Message Service, or JMS. The JMS API is designed to do for messaging in the enterprise what JNDI does for naming and directory services and JDBC does for database access. JMS is an API that's designed to provide a common facility for enterprise messaging, leaving the underlying implementation of the messaging to whatever application server or other enterprise messaging software technology you wish to use. This is an exciting advance for those involved with the creation or use of message-oriented middleware (MOM) ­ and especially for Java developers who need to utilize such facilities within their own products. With JMS you should be able to write one set of code for messaging against the JMS API and then use it across any messaging system provider that offers JMS support.

Despite recent high-profile attacks, application developers often consider security something to tack on at the end of a project, and history encourages this approach. It's unusual to see security considered a fundamental design element in a programming language.

This month the Java platform segues into the new millennium. These are very exciting times; 1999 was a crucial year in the acceptance of Java in the enterprise as one of the key drivers of e-business. It's ironic that applets ­ the components of Java that helped propel it into the mainstream of Internet applications ­ currently occupy a backseat in the vehicle that propels Java into the 21st century. During the year gone by, the focus was on server-side Java, as predicted last year by several industry pundits ­ more precisely, on Java in the middle tiers of distributed computing.

Java programs can use the JDBC API to access relational databases, thereby cleanly separating the database system from the application. This approach holds the promise of cross-database portability, i.e., "write once, run on any database." In practice, several stumbling blocks stand in the way of fulfilling this promise.

There are several books and articles out there on dynamic-content generation technologies such as CGI, NSAPI, server-parsed HTML, server-side JavaScript, Active Server Pages and ColdFusion. Recently, Java Servlets and JavaServer Pages (JSPs) have emerged as a very popular technology and a lot of material has been written about them. Most of the articles focus on programming model features, ease-of-development issues and integration with tools. However, an increasing concern of Web site developers is to develop sites that can scale to a large number of hits. This is especially true of corporate software developers and those building the brand-name dot.com sites of tomorrow. This article focuses on how Web developers can design their server-side applications for scalability and performance using Java Servlets and JSPs.

Rumor, they say, is a great traveler – if developers were in any doubt about this, they need only monitor the worldwide rumor-mill surrounding the rivalry between Sun and Microsoft…

Sun Leads Industry Cavalry Charge to 'Liberate' the Internet from Microsoft

Is the writing on the wall for Open Source? This is an i-technology tale involving Sun's J2EE specifications, a well-respected Californian software company, and the inflamed passions of the international OSS (open source software) community.

Full text of JDJ'S exclusive interview with Lutris's foremost critic, George C. Hawkins. 'Their behavior is a complete slap in the face to all those in the user community' says Hawkins.

One of the great things about the JavaBeans specification is the flexibility it affords component developers in how they package their beans. As a bean developer, all you need is a class with a no-argument constructor that supports serialization and it's a bean. If you follow some simple naming conventions, most integrated development environments (IDEs) can tell enough about your bean to be able to use it for visual application development. While this is sufficient for some simple beans, the beans specification also provides ways for bean developers to explicitly give information that the IDE can use to assist the application developer in using the component. This article explores some of the ways that bean developers can make their components more usable by application developers through the use of custom property editors and customizers.