Hans Bergsten has worked in the computer industry for 18 years, with everything from IBM mainframes to PCs.
Java Articles at the Web Developer's Journal - Java programming tutorials, applets, beans, servlets and more.
We've tried to assemble a collection of articles
about Java to help the beginner or the real Java gurus. If you have questions
(or answers) concerning Java, please visit our Java Discussion
Group.
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Java Hub
If you have questions about Java development
you have arrived at the right place. Scroll down for articles about servlets,
product reviews and "how to do it" articles. We also maintain a Java discussion
group.
Taking Notes on Java
Edward Tanguay sings the praises of a very important language.
The
Bluffer's Guide to Java
Can't tell your Beans from your Applets? Wondering
if a Servlet is a small server waiting to grow up? Read our compact guide to Java
and you'll soon be dropping JAR, JVM and JSDK into casual conversations along
with the best of them. Nobody will bother listening to you, but they'll still
be mightily impressed.
Java: Coming
to a TV near you!
The new Java TV API holds the promise of Java-based
interactive television using set-top boxes.
Java
vs Other Web Application Technologies
(The JavaBoutique) Selena Sol, author of JavaBoutique's
Introduction to Java, gives an in-depth comparison of Java and other development
languages such as dHTML, ASP, and Perl.
Agent
Communication
Agent technology is becoming more prevalent as the availability of network access,
and the demand for the end-uses of agents, become greater.
Java Web
Server in Brief
A simple, dependable, and inexpensive ecommerce solution for small businesses
is proposed.
JSP: The Back Door into Java
Edward Tanguay discovers JSP, and finds it finally allows him to put his theoretical knowledge of Java to use, and hence, get a foot into the Java programming world.
Building
Java Server Pages
A detailed look at building JSP pages. Should you
use JSP or servlets? It depends on the ratio of markup to code. Here you'll also
find a guide to the different varieties of tag, and details about the main tags
such as <jsp:useBean> and <jsp:setProperty>.
Site User Logon with XML, Java Beans and JSP
During this tutorial we will use XML and Java Server Pages to verify a user's logon - and then store the results in a session Java Bean for easy access.
Serving
Dynamic WAP Content with Java Server Pages
Here's how to create dynamic content for WAP-enabled
mobile phones using the Wireless Markup Language (WML) and Sun Microsystems' Java
Server API. Our Java Server Pages application displays regularly updated appointment
data for someone on the move, such as an appliance engineer making house calls.
Object
Persistence Made Easy
With object serialization, your Java applets and
applications can save and load the state of objects to disk or over a network.
In this article, we'll examine the benefits of object serialization, and how to
implement it in your own programs.
Servlets
Intro
to Servlets
Java servlets are making headlines these days, claiming to solve many of the problems
associated with CGI and proprietary server APIs. In this article I will describe
the overall servlet architecture and what you need to develop your application
with servlets. I will use several code examples to show you how to use the Servlet
API, and compare it with CGI and proprietary server APIs where appropriate.
Internationalizing
Servlets
How to use the Java Internationalization API to build server-side code that alters
its output based on the location and language of the user. We demonstrate the
use of the API by building a simple method which displays a product entry for
a shopping cart application.
Using
the HttpSession object of the Servlet API
The Java Servlet API represents an elegant and powerful way to shift processes
from client to server, and offers a number of advantages over CGI. These advantages
have certainly been enumerated so that most developers are aware of the servlet
advantage. However, some of the details of the servlet architecture may at first
seem daunting. Here's a short introduction on one aspect of writing servlets:
the HttpSession object.
Improved
Performance with a Connection Pool
Establishing a connection once and then using the same connection for subsequent
requests can dramatically improve the performance of a database-driven Web application.
Since Servlets can keep information between requests, a database connection pool
is a straightforward solution.
As Web sites get more and more interactive, customized and dynamic, developers
turn to technologies that allow them to do more than the first-generation tools
can handle. One technology that is rapidly replacing CGI and Perl scripts as
the preferred choice for dynamic Web sites is Java Servlets.
July 18, 1998
Ask Marc Mnich, developer of the Virtual Memorial Web site. "[The] initial design of the system was CGI-based using perl and the same database backend. I have found the Java
Servlets to be far superior in terms of performance (mainly due to threading and
JDBC) and stability," he says. The Java Servlet API is part of the Java
specification in JDK 1.2. A Servlet is executed on the server, like GCI scripts,
but instead of creating a new process for each request, all Servlet requests are
handled in the same process by separate threads. Servlet-based applications
therefore avoid a lot of overhead processing. Using threads instead of processes
also means that a Servlet can keep data persistent between requests. For
instance, a pool of database connections can be shared by multiple requests and
frequently requested information can be cached. Threading and persistence makes
it much easier to develop high performance solutions.
A Servlet-based solution is a standards-based solution. It means it works with what
you have today and scales to what you need tomorrow. The Servlet API is
supported natively by a number of Web servers, such as JavaSoft's Java Web
Server (JWS) and O'Reilly & Associates' WebSite Pro. For other popular Web
servers, like Netscape's Enterprise Server and FastTrack Server, Microsoft's
Internet Information Server (IIS), StarNine's WebSTAR, and Apache, there are
Servlet Engine add-ons from companies like Gefion Software, Live Software, New
Atlanta and IBM. Application servers with load balancing and sophisticated
administration features, like ATG's Dynamo and NetDynamics, support Servlets as
well. Since Servlets can use all Java APIs, they are easy to integrate with
other parts of the IT infrastructure. All major databases can be accessed
through JDBC, directory services through JNDI, and advanced distributed services
through RMI and Java IDL.
Performance and scalability are important concerns when selecting a technology
for your Web site development. A popular site can receive an enormous number of
requests per day. With the inherited threading and techniques like database
connection pooling and caching, Servlet-based solutions are well fit to handle
the pressure. "Sony Corp.'s The Station isn't just another Internet site with
games, shopping, and chat groups. It's the largest server-side Java site on the
World Wide Web, receiving 100 million hits a week," reports Bronwyn Fryer in an
article in the January 19 issue of Information Week. At traffix.com, an ad
banner exchange service, Servlets are serving up to 190,000 banners per day.
virtualmemorials.com receives around 50,000 hits per day, most of which are for
servlets. Servlets are used to power Proxicom's solutions for online
communities, with features like discussion forums, chat rooms, calendars and
more. "Our application is capable of returning a 'dynamic ptml page' within a
few hundredths of a seconds," says Rich Andrews at Proxicom, Inc. Servlets also
deliver membership services at developer.java.sun.com, provide access to contact
information and resumes at www.qcommand.com, sell software at javashop.sun.com.... The list goes on and on.
If your Web site could do more for you than it does today, take a closer look at
Servlets and Servlet-based products and solutions. The technology is here today,
providing valuable services 24 hours a day, 7 days a week at a Web site near
you.
Hans Bergsten has worked in the computer industry for 18 years, with everything from IBM mainframes to PCs.
