EJB 2.1 Inheritance

by
ONJava Newsletter for 09/05/2002

Dear Reader,

This week on ONJava.com, EJB 2.1 columnist Emmanuel Proulx begins a series of articles describing the techniques for putting inheritance and polymorphism back into entity beans. Entity bean inheritance isn't going to make your life that much easier. It may make the code smaller, with less repetition and easier maintenance. However, there is some work involved (especially for finders and table mapping), which may negate these benefits. But if you have many objects that are based on each other, using inheritance may result in the most maintainable system.

Also this week, Giuseppe Naccarato discusses nonblocking sockets, introduced in Java 2 Standard Edition 1.4. You can use these sockets for Internet communication between applications, without blocking the processes. In this article, you'll learn what a nonblocking socket is; how it works; and in which contexts it can be useful.

And finally this week, ONJava.com concludes a four-part book excerpt series on working with complex data types from O'Reilly's "Java and SOAP." In part four, learn about returning custom types, using a stock market example.

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Talk to you next week.

Steve Anglin
O'Reilly Network Java Editor
sanglin@oreilly.com

This Week's Featured Articles

EJB 2.1 Inheritance, Part 1
The principles of object-oriented programming are encapsul- ation and inheritance. Enterprise JavaBeans handle encapsul- ation just fine, but what about inheritance? In this article, the author attempts to apply inheritance to EJBs.

Introducing Nonblocking Sockets
Nonblocking sockets, the new I/O API in J2SE 1.4, allow I/O operations on a channel without blocking the processes using it. This will allow for asynchronous high-performance read/ write operations that will totally alter the techniques for developing socked-based applications.

Working with Complex Data Types, Part 4
This is the last in a series of book excerpts from "Java and SOAP" on working with complex data types. In this excerpt, learn about returning custom types, using a stock market example.

ONJava.com News and Weblogs

On Running a Java SIG
For the past two years, William Grosso has been running the Software Development Forum's Java SIG. It's still not quite clear how I wound up doing so, but it's been interesting and it's been educational.

J2EE Open Source
It looks like Steve Anglin weblogged this a few days ago, but I just came across the response Marc Fleury (head of the JBoss group) posted to Scott McNealy's comments about the conflict between the J2EE licensing model and open source approaches. Still, it's ground worth treading again.

The Death of EJB As We Know It?
Stop and consider, if you will, what this posting to theserverside.com implies: that somebody not only believes that "alternatives" to EJB are useful and relevant things, but that they could make a business case out of it and stake a company's fortune on the idea.

Meerkat Java News
For more Java news, check out O'Reilly Network's Meerkat service on the ONJava.com home page or go to oreillynet.com/meerkat and select Java as subject.

New O'Reilly Java Books Look for these new O'Reilly Java books: "JavaServer Pages, 2nd Edition," "JXTA in a Nutshell," "Java NIO," and "NetBeans: The Definitive Guide."