Installing the Java Plugin
Because of inter company politics, Microsoft does not ship a copy of the Java plugin with its Internet Explorer web browser, and your users may find the idea of downloading and installing such a piece of software intimidating. Fortunately Sun has created a system whereby a user without the plugin will be offered the chance to download, install and run the plugin, fairly automatically. The users still face the delay of downloading a 5MB file the first time they try to access an applet, but this is a one off problem, and with many users having improved bandwidth, this should not be an insurmountable problem. Also you may modify the code to access a copy of the plugin on your local network to reduce the download time still further. The Java plugin is installed as an option when you install the Java Development Kit, so as a student on this course you should have it installed by default.
To check for the presence of the plugin and to re-direct the users you can process your html using a tool from the JDK called htmlconverter. This is a small graphical tool that allows you to select the directory and file types you wish to convert, and it then modifies your HTML to include the code needed to re-direct users who do not have the plugin installed.
You can find out more about the htmlconverter from
http://java.sun.com/j2se/1.5.0/docs/guide/plugin/developer_guide/html_converter_more.html
Java WebStart
If the you want to deploy Java code that needs greater access than the security of Applets, another distribution system is Java WebStart. WebStart is like a web server based installation system that gives the benefit of making it easy to update applications. WebStart uses the standard HTTP protocol, so it should not have problems with FireWalls. If the application does require greater access than an Applet you will be asked if you are happy to give this permission. This means that you should be confident of the source of the program before you install it.
You can find out more about Webstart from sun at
http://java.sun.com/j2se/1.5.0/docs/guide/javaws/developersguide/faq.html
And you can see an interesting tool for creating UML diagrams that can be installed via WebStart at