An Overview of the Java Market
by Don Larson
It's hot. It's happening. So should you be using it? Explore Java's special status in this overview of Java and the Java market.
Despite its short time in the world, Java has been adopted faster than any
other
programming language in the history of computing. Riding the coat tails of
a "new media"
explosion, the upstart language has become synonymous with the Internet.
However, Java is quickly outgrowing the confinements of its early
bell-and-whistle days,
finding itself used more and more as a robust, all-purpose platform for
building full-
featured applications in an increasing number of new niches. Last year,
this versatility and
scaleability led over 200,000 programmers and a third of all companies with
more than
5000 employees to begin using Java in their application development,
according to Sun
Microsystems.
With the advent of an even more robust Java in the latest 1.1 release, and
industry support
from companies like Netscape, Cisco and IBM, who pooled $100 million to form a
venture-capital resource called the Java Fund, the numbers associated with
Java in 1997
will be even more astounding.
Java's rise has been meteoric, indeed. And, as with any new star, its every
move has been
surrounded with hoopla. For the past year or so, you've been hammered with
hype and
pummeled with puns. What you may have missed amid the fanfare, however, are the
basics of what Java is all about: what it is, and what it can do for you.
To that end, Web Developer® presents a detailed look at Java designed to go
beyond the
buzzwords and get down to what really separates Java from the pack. In the
process, we'll
also illustrate the many and various applications that developers in the
Java market are
finding for this promising young language.
WHAT IS JAVA?
An "official" definition of the language usually goes something like this:
Java is a simple,
object-oriented, multithreaded, portable, platform-independent, secure
programming
environment used to create applications and smaller programs known as applets.
A useful definition, if you enjoy Java jargon. But what do these
designations mean in real-world terms, and how do they differentiate Java from its predecessors?
Let's take a look:
Simple:
Java is basically a "stripped-down" version of C++, in that many of
the rarely-used
and confusing features of the latter have been removed. Java also does its
own garbage
collection and eliminates pointers, thereby easing the task of memory
management and
debugging (We'll take a more detailed look at how Java compares to C++ and
other
popular languages later in the article). There are two primary benefits to
this simplification:
it makes migration to Java easy for the majority of programmers, and it
creates a compact
language that transmits well over networks.
Object-Oriented:
In Java, everything is an object, or at least attached to
an object-even
global variables. Among other benefits, this makes it easier to reuse
objects with other
objects. Also, instead of multiple inheritance (subclassing), as in other
O-O languages like
C++, Java supports inheritance through interfaces. Interfaces are sets of
method definitions
that basically describe classes and how they interact with the world. Using
interfaces, a
Java class can, at least in theory, borrow the methods of any other class.
Therefore,
developers don't have to worry about inheritance at design time, taking a
lot of the planning
and pain out of creating interfaces.
Multithreaded:
Applications written in Java are capable of handling many
operations
simultaneously. While it's possible to do this manually in other languages,
Java's
multithreading capabilities are integrated directly into the language as
primitives. By
providing better performance and responsiveness, multithreading makes up
for some of the
performance Java sacrifices as an interpreted language.
Portable:
Java is able to run on almost any computer regardless of its
platform or operating
system. This makes it perfect for heterogeneous networks like the Internet
and corporate
intranets.
Platform-independent: Applications written in compiled languages like C++
must be ported
to every platform and OS you want them to run on. In contrast, Java is an interpreted
language. Rather than native machine code, the Java compiler first
translates applets into
bytecodes: a high-level, machine-independent code only comprehensible to
the Java
interpreter, or virtual machine. This bytecode is handed at runtime to the
Java Virtual
Machine (VM), which then translates these instructions into native machine
code on the fly.
Therefore, instead of every application, only the VM must be ported to each
platform. A
number of vendors have also introduced "just-in-time" compilers that allow
Java apps to be
custom compiled directly into the machine language of a particular
platform. Bypassing the
VM, JIT compilers enable you to trade portability for greatly enhanced
performance.
Secure:
Any time you are downloading executable code on a network, security
is an issue.
Because Java was developed from the ground up to be used in a network
environment,
however, it has a number of built-in security features.
Foremost among these is the Java VM, which acts as a mediator between Java
bytecode
and a CPU. It does this by creating separate and confined memory for
applets to run in,
then screening each instruction before it is passed to the CPU.
Specifically, applets must
run in a protected space that prohibits access to the local disk -- the Java
"sandbox." Applets
loaded over the Internet are not, by themselves, able to read or write
files, start other
programs, load libraries, or define native method calls.
The 1.1 release of Java does provide for a finer level of control over
security, however,
namely in the form of digitally signed classes. This will make it possible
to open up
objects, like a user's hard drive, to an authenticated applet.
ADDING IT UP
What all these features add up to is a programming language ideally suited
to developing
programs for delivery via the Internet and corporate intranets. And because
Java applets can
run within Java-enabled browsers already in wide distribution, the Java
environment is
automatically equipped with a thin client that is as close as you can get
to zero
administration. In addition, applets reside server-side and are downloaded
to the client
upon request, so Java applications are easy to extend and revise as needed.
WHAT'S IT GOOD FOR?
Even though Java sounds great on paper, many developers still question its
real-world
utility. This is perhaps the most important question that the Java
development community
will have to answer in the coming year: "What can you really do with Java?"
This is not to
say, however, that the Java market doesn't already bear the fruits of
Java's network-savvy
characteristics and functionality. In fact, given the short time the
language has been
available as a development platform, the variety and robustness of
Java-based applications
currently on the market are strong indications of Java's usefulness -- and of
things to come.
For a better perspective on the range of applications Java is capable of,
including how these
apps demonstrate many of the unique features discussed above, here's a
quick sample of
Java in its many settings:
Web sites:
Although Java may be outgrowing its roots, it hasn't forgotten
them. Java
animations, special effects and interactive applications are still some of
the best ways to
make a static Web site come to life. For example, applets like "nervous"
text, LED displays
and scrolling marquees are now ubiquitous on the Web. These animations have
a distinct
advantage over other methods of imparting motion, such as animated GIFs, in
that applets
can be interactive.
Take, for instance, c|net's "news ticker" applet, in which
visitors can
click on a scrolling list of headlines and be taken directly to the
appropriate page.
Interactive, animated imagemaps, as the Penumbra Software site
demonstrates, also add a whole new level of
cool, with
elements like buttons that change color, activate pop-up menus and even
play audio as a
mouse moves over them.
While this type of content can be created in other ways, such as Macromedia's Shockwave,
applets take advantage of Java's platform-independence and widespread
browser support,
so they don't require users to download more plug-ins or otherwise upgrade
their software.
Java is capable of producing full-featured interactive applications for a
Web site. Java-based programs like EarthWeb Chat and Eastland Data
Systems'
Internet Shopping Cart are quickly
replacing applications that
previously required separate client software.
Java has also been used in the areas of indexing, searching and data
mining, as products
like Innotech's NetResults and Cadis Inc.'s
Krakatoa
attest. Along with features like cross-platform,
multithreading and even
drag-and-drop interfaces, these applications also take advantage of Java's
distributed
computing capabilities to download executable content to the client.
Flattening the architecture in this way not only removes much of the server
strain that
results from the older, CGI-based models (which require a separate server
connection to
update pages), but also grants the user a higher degree of interactivity
and responsiveness
in their experience. Using the NetResults search engine, for example, users
are not simply
given a page of static hyperlinks, but an applet that displays a visual
representation of the
requested data that can be interactively refined and otherwise manipulated,
without
additional connections to the server.
Corporate intranets:
In addition to the sample applications just listed,
enterprise developers
and vendors have found special niches for the Java platform. On a more
abstract level,
Java's robust and dynamic characteristics make it perfect for prototyping,
not unlike other
interpreted languages like Tcl. Java's lack of pointers enables programmers
to develop
programs efficiently, without the constant interruption of memory
corruption. And because
Java is a strongly-typed language, method invocation errors are reported at
compile time,
rather than run time.
More tangible uses, like standard business applications, are also being
developed in Java.
For instance, Corel recently introduced Office for Java, a suite of
business applications that includes Java versions of the company's popular word
processing, spreadsheet and presentation software. In many ways, the suite
represents the
desktop of the future. The "fat" client of old is replaced by a
network-centric approach in
which the applications reside on the server and are seamlessly downloaded
to the client as
needed. Furthermore, the suite is completely compliant with JavaSoft's
JavaBeans
component model, which means the applications will be easily extensible via
third-party
modules.
It is in the area of Web-to-database connectivity, however, that Java's
most significant
enterprise utility lies. JDBC, Java's database interface, provides a
platform on which
programmers can bypass the traditional client-server architecture by
creating single front-
ends that deliver uniform access to almost any brand of SQL database via
any Java-enabled
browser on any platform. Many vendors are also using Java to develop
end-to-end, server-
based database solutions written completely in Java, as demonstrated by
products like
Infospace's SpaceSQL. Putting Java in the database
equation
produces a number of benefits for administrators and end-users alike,
including enhanced
performance from multithreaded servers, automatic installation and
platform-independence
for clients, and interactive query and drill-down capabilities for consumers.
Stand-alone applications:
Finally, the fact that many developers are
releasing full-featured,
stand-alone applications that are 100% Java attests to the scaleability of
the platform. One
of the best-known examples in this category is JavaSoft's own Web client,
the HotJava
browser. Initially released as a
"proof of concept"
product for Java, HotJava lives up to its calling, demonstrating Java's built-in networking
functionality as well as its extensibility and versatility. The browser
interface, for instance,
is fully customizable, so that both end-users and administrators can
configure it to suit
tasks ranging from a desktop browser or intranet client to an interface for
an "information
appliance" like a kiosk.
As the network computer, or NC, and Java's operating system, JavaOS, begin
to show up
on more desktops, so too will more Java-based applications.
JavaSoft's HotJava Views is a
forerunner to
these types of network-based computing applications. Views 1.0, the first user
environment for the JavaOS, contains an e-mail client, calendaring program,
name
directory access and a HotJava browser. The 2.0 release will be entirely
cross-platform,
running on any server with a Java VM. Among its other firsts, Views sports
a true zero-administration client, greatly reducing the resource drain commonly
associated with
traditional client-server applications.
Of course, vendors other than JavaSoft are building full-scale applications
on top of Java.
Perhaps one of the best examples is Marimba Inc., a
company that
has taken Java into the push technology market. Castanet, the company's
channel software,
takes advantage of Java's distributed, scaleable and platform-independent
capabilities to
automatically distribute and maintain software and content on a
subscriber's desktop. The
product enables content providers, MIS departments and even software
vendors to deliver
applications ranging from entertainment Web sites to full-featured business and
productivity software over private networks and the Internet.
IS IT WORTH THE SWITCH?
Once you've answered the question of Java's worthiness as a development
platform, a
second question rears its head: "Why choose Java over the platform(s)
you're currently
using and already familiar with?" While many of the features described
above provide at
least a partial answer to this query, a side-by-side comparison of Java and
its peers will
help to clarify it more.
Java vs. JavaScript:
Unlike the name suggests, JavaScript is not a
by-product of Java. In
fact, Netscape's higher-level, user-friendly scripting language was
developed separately
from Java (and was codenamed, interestingly enough, "Mocha"). JavaScript is
designed to
fill the gap between CGI and Java, complementing both in the process.
Unlike Java, which
is compiled into bytecode on the server, JavaScript is a scripting language
that is fully
interpreted by the client. JavaScript embeds built-in, extensible objects
directly into HTML,
but contains no classes or inheritance. This simplification is both a pro
and a con for
JavaScript: while it limits the language's functionality, it also enables
you to build very
lightweight, cross-platform programs that help reduce strain on the server.
Ultimately,
JavaScript was designed to provide an easy way for Web developers to create
interactive
Web pages, not create stand-alone applications like Java applets.
Java vs. ActiveX:
Comparing these arch-rivals is a lot like the proverbial
apples and
oranges debate, in that Java is a programming language and ActiveX is a
component
framework. In this way, ActiveX is more akin to the JavaBeans component
model than
Java itself. Basically, ActiveX is a system for managing code written in
other languages,
namely Visual Basic, and for distributing and interchanging this code on
the fly.
Two of the biggest concerns with ActiveX center around its portability and
security.
Because it is based on Microsoft's OLE and OCX components, ActiveX is
really best
suited for applications in a primarily Windows-based environment. And
because the
ActiveX security model allows binary code to be executed on the host
machine's hard
drive, rather than in a protected space like the Java VM, malicious attacks
and viruses are a
real concern. Ultimately, Microsoft plans to address these areas, lending
ActiveX more
platform-independence and providing digitally signed code. As many developers will attest,
however, "vaporware" is a tough platform to build on, and Java's second
revision is
available today.
Java vs. C++:
Many of the similarities and differences between Java and its
precursor,
C++, have already been mentioned. C++ is a low-level, fully-compiled
language primarily
designed as a platform for large-scale applications in which speed is a
major concern.
While C++ is many times faster than interpreted languages like Java, it
sacrifices portability
in the process. And Java's speed deficiencies are being addressed by a
faster 1.1 VM and
the JIT compilers currently available. Moreover, considering the widespread
adoption of
Java, chances are it won't be an interpreted language much longer, and thus
won't be
forced to rely on these stop-gap measures for better performance. In
addition, C++
programmers must implement memory allocation and garbage clean-up manually,
which
often leads to many hard-to-find bugs, general protection faults and system
crashes.
The biggest advantage Java holds over C++, however, is its tight
integration with the
Internet. This allows Java to adapt and evolve alongside the Internet more
readily than other
languages, making it a prime platform as applications move from
traditional client-server
models to Internet- and intranet-based paradigms.
Java vs. Perl:
Perl lies somewhere in between low-level languages like C++
and high-level
scripting languages like JavaScript and Tcl. Perl has evolved into a
language that has much
in common with Java: it's object-oriented, secure, robust, dynamic, and
architecture-
neutral. Perl contains powerful functions for manipulating strings of text.
Therefore, it is
very good at finding, extracting, and recombining data with remarkable
concision. This
makes it perfectly matched to the needs of CGI scripting, where Perl is
most commonly
used today.
However, server-based CGI programs, as mentioned previously, place additional
connection and processing burdens on the server. As the number of users
increases, the
performance of the server typically declines, meaning Perl and other common CGI
languages don't scale well for larger applications. Java, on the other
hand, shifts most of
the processing duties to the client in the form of downloadable, executable
content.
JUST DO IT?
In the end, whether you decide to "just do it in Java" will depend on the
customer base
your application will serve and the criteria it must meet. If, by chance,
you have to deliver a
large-scale, high-performance application that will run in a Windows-only
environment,
then platforms like C++ and ActiveX are probably still your best option.
If, however, you
are commonly asked to produce interactive graphics, front-ends or
full-scale applications
that will run securely on the largest majority of clients connected to the
Internet or operating
on the heterogeneous networks of a real-world intranet, then it's time to
add Java to your
application development arsenal.
Don Larson is Associate Editor of Web Developer®.
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