[TriLUG] ajax presentation - why is javascript good, but java bad?

Rick DeNatale rick.denatale at gmail.com
Fri Mar 10 12:33:22 EST 2006


On 3/10/06, Wing D Lizard <wingedlizard at nc.rr.com> wrote:
> Why is javascript good, but java bad?
>
> It seems like you could do something similar using using
> plain old java ( like sending diff, instead of reloading whole
> page).
>
> My java programming has been apps only ( like air traffic control
> display for military) -- no applets.  Is it just that java within
> a browser is bad?

As some of my British friends are wont to say, it's "Horses for courses."

Java and JavaScript are far less related than the name suggests.
http://www.dannyg.com/ref/javavsjavascript.html

Java started out as a full-fledged language for programming embedded
devices, then found it's marketplace as a general-purpose internet
programming language.  It seems to have found its niche these days as
a server-side language first, with some usage for embedded devices
(J2ME/OSGI...). It's been less successful as a client language, or as
a browser extension languages (applets) because it's less generally
available, and to some extent less suitable.  Also Sun jealously
protects the licensing of the Java trademark which has restricted it's
success in open source environments.

JavaScript was born as Mocha, Netscape's implementation of ECMAScript,
then renamed LiveScript and finally JavaScript which was really a
marketing move on the part of Netscape at the time when Java was THE
hot buzz word.

>
> Java would have to be faster than javascript, easier for
> programmers to program.  I would expect the tools to
> be better as well ( maybe not ).

Not necessarily.  Since JavaScript was designed to be a scripting
language for browser extensions, it's lighter weight than Java,
doesn't require a lot of things which give Java a heavy footprint, and
should in general be quicker.

It also should be easier to learn being a simpler language, in some
ways it's a natural extension of HTML which adds some facilities to
make a web page executable and not just a static description of the
page content.

And this is coming from someone who spent a good deal of his
professional life over the past several years working on selling Java
technology and working on Java standards.

To me the interesting thing about AJAX is that it's yet another spin
of Myer and Sutherland's "Wheel of Reincarnation" described in their
1968 paper on designing interactive graphics systems, in which they
described the difficulties of "correctly" partitioning compute power
between a server and a client/terminal/display list processor.
http://www.cs.unc.edu/~lastra/Courses/Papers/Myer_and_Sutherland-On_The_Design_of_Display_Processors.pdf

The wheel has been spinning ever since. Fairly dumb terminals such as
VT100s vs more "intelligent" ones with local editing capabilities such
as the IBM  327x series.  Personal computers being used as standalone
devices then emulators of dumb/smart terminals. The first web browsers
were fairly dumb clients although with rich presentation capabilities.

In effect, AJAX turns the web browser into an "intelligent" terminal
capable of making local decisions instead of just rendering html.

--
Rick DeNatale

Visit the Project Mercury Wiki Site
http://www.mercuryspacecraft.com/



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