Running JAR-Packaged Software

In The Java Tutorial, the lesson on running jar package software opens by introducing three scenarios:

  • Your JAR file contains an applet that is to be run inside a browser.
  • Your JAR file contains an application that is to be invoked from the command line.
  • Your JAR file contains code that you want to use as an extension.
The second of these I have already covered, I have no idea what the third means, so I shall focus on the first. I shall create an experimental page on my web site to test the line by line. From the example given:
"open brace"
applet code="TicTacToe.class"
archive="applets/TicTacToe.jar"
width="120" height="120"
"close brace"
I shall post: 
"open brace:
applet code="AMJFormA002.class"
archive="ActiveMathJA002.jar"
"close brace"

I have removed the height and width parameters because they don't apply to my app.

When I refresh my page I get a brief flash of the java logo, then a long error message.

Ages ago, I read that something needs to be installed on the server side, and when I checked with my ISP they replied that they didn't have it and weren't planning to any time soon. Perhaps bad people plant java applets in web pages to do bad things. Be that as it may I must find out what it was. I shall follow the link to the Applets lesson.

Comments

Post a Comment

Popular posts from this blog

A few notes on JavaScript

I am one the 99% of the world who has long nursed the misconception that JavaScript has something to do with Java. And why not? The name sort of implies it. It was only after I searched without success on the Java Tutorial site for some mention of JavaScript that I stumbled across the knowledge that JavaScript was in fact developed by Netscape, under the name LiveScript. Armed with that knowledge, it is not surprising to find the best reference information on Mozilla site. According to Wikipedia , the nonsensical name choice had something to do with Netscape wanting to cash in on the popularity and cachet of Java, and Sun wanting support for Java technology in the then popular Netscape browser. For a while only the Netscape family of browsers supported JavaScript. Microsoft later produced what it calls JScript to run in its browser. JScript is similar but not identical to Javascript. According to Foldoc JavaScript runs a hundred times slower than C , and ten
Read more

Forum Comments on Java Applets

It is so long since I last posted on the once was Sun/Java now is Oracle developer forum my account seems to have been ditched. While I wait to have it resurrected I've done a little searching in the Java Database Connectivity (JDBC) forum using the search term "Applet". My first search, using the default 3 month period, yielded nothing. No one had posted anything about or even mentioned Applets in the last three months. So either they are very easy to use and work very well, so hardly anyone has any problems with them, or maybe ... not very many people use them at all. My stomach was beginning to churn a bit, when I extended the search period to the current year - and with good reason. Somebody, a little bit like me I think, had written a game in an applet, and wanted to record top scores in a database. He described his connection problem in this thread , and the first reply began: Doing JDBC calls from an Applet is such a bad idea that I am glad y
Read more

Creating a Custom Swing Component

Image
I always return to my blog when I'm stuck, and I'm stuck right now. I want to create a custom Swing component. Specifically, I want something like a JProgressBar , with the following changes: In place of a flat Foreground color, I want a rainbow spectrum, showing only the red range for low Values, and the whole spectrum for values close to the Maximum value; Instead of a rectangular box, I want the progress "bar" to take the shape of a normal, or Gaussian, distribution curve; I want progress to be displayed by the area under the curve, rather than by a simple linear scale along the x axis. It's not that there isn't stuff out there. I have five tabs open in my browser, specifically addressing the creation of custom components in Swing, as well as the source code for the JProgressBar . It is that, like everything to do with Java, it is bloody difficult to read. I shall begin from the horse's mouth as it were, with an article on the Java
Read more