Understanding Java Browser Issues

As previously mentioned, you can use Java in a client, server, or mixed solution. The problem with developing either a client or mixed solution is that you have to consider the user 's browser. The media has documented the combat between Sun and Microsoft over the JVM. (See the story at http://archive.infoworld.com/articles/hn/xml/02/12/05/021205hnmsblames.xml?1205tham as just one example.) Microsoft, as usual, decided to produce its own version of the JVM, which is incompatible with Sun's version. Some users might have this incompatible version installed, even though Sun won a lawsuit over the issue and Microsoft no longer produces it.

The latest twist in the battle is that some versions of Windows no longer come with the JVM installed, which means that the client can't run your Java application at all. In some cases, Microsoft is withdrawing products from the market earlier than anticipated to ensure they meet the court -ordered deadline for restricting distribution of their custom JVM solution (see the eWeek article at http://eletters.eweek.com/zd1/cts?d=79-353-2-3-67152-42164-1 for details). Microsoft originally shipped Windows XP without a JVM, downloading the JVM on demand, rather than supplying it as a default (see the InfoWorld story at http://archive.infoworld.com/articles/hn/xml/02/06/18/020618hnjavasupport.xml?0620thap for details).

Sun is also active in the JVM battle. For example, the company is trying to get around the Windows JVM problem by signing individual companies to distribute the Sun version of the JVM (see the InfoWorld article at http://www.infoworld.com/article/03/06/11/HNjavadell_1.html for details). The two companies are still in court over this issue (see the story at http://www.infoworld.com/article/03/04/03/HNmsorder_1.html). Because of this contention , you can't be sure which version of the JVM a client has or even if the client has the JVM installed.

Even if the client has the JVM installed, crackers have made Java one of their tools of choice. Consequently, many people turn off support for the JVM in their browsers. This task is amazingly easy with products such as Internet Explorer. Because you don't know whether the client has the JVM installed, telling them to turn the JVM on in an error message is unlikely to produce the desired results in many cases.

Finally, it might seem like everyone would have a JVM installed and all the proper browser support, but that's not true. Many browsers simply don't have the required support. You can view the Webmonkey charts at the following locations for specific platform support of Java.

• Windows http://hotwired.lycos.com/webmonkey/reference/browser_chart/index.html

• Macintosh http://hotwired.lycos.com/webmonkey/reference/browser_chart/index_mac.html

• Linux http://hotwired.lycos.com/webmonkey/reference/browser_chart/index_nix.html

• Other http://hotwired.lycos.com/webmonkey/reference/browser_chart/index_other.html

The bottom line is that you have to know the client capabilities of the users of your application or develop a server-side solution. Java is a great solution because it's so flexible, but it also carries a number of problems that you might not run into with less flexible or less capable solutions. You need to decide whether the potential browser problems with Java are going to interfere with your Google Web Services application.