Applets and web browsers

Java Applets and web browsers

In the early days of Java it was assumed that its main area of success would be in Applets, small programs that get executed within the browser rather than on the web server. For various reasons applets have turned out to be a minority sport on the web. They suffered from performance and compatibility problems. Much of the compatibility issues stem from the different implementations from Microsoft, Netscape and Sun.

Microsoft has never supported the Swing libraries and Netscape was late to support them. It was also found that few web sites actually needed to have code execute within the browser and where it was needed the needs were fairly trivial and would execute more quickly using a scripting language such as JavaScript (almost no relation to Java at all). It is hard to persuade inexperienced users to download a 5 megabyte install program simply to get some feature working on your website unless they have a very pressing need for that feature. Many website designers have decided that Flash offers most of the programming features of applets but with better performance and wildly better control over appearance.

The Java Plugin

There are areas where nothing but an Applet will address the problem and the lack of compatibility across browsers was a thorny problem. As a result there was a minor industry in programming AWT applets that took account of the quirks between the Netscape/Microsoft/Sun implementations of Java. This ridiculous lack of standards was significantly addressed by Suns Java plugin. This is a kind of bridging technology that allows Applets to run using the standard Java runtime shipped by Sun in almost any browser.

The Java plugin gives a standard JVM target across all the major browsers.

The Plugin Tray icon

Under windows, when you access an applet the Java Plugin icon will appear in your system try in a similar way to the following screen shot (the arrow points to the icon)

The plugin will run in both the Netscape and Microsoft browsers and gives programmers a single platform as a target for their programs. I recommend the plugin as the preferred way to execute Applets as you can avoid many incompatibility problems between versions of Java.