|
Website by Michael Horowitz 
|
|
Website by Michael Horowitz
|
|
|
| Test the version of Java your browser is using |
A Java program in a web page is called an applet. Most web browsers can run Java applets/programs. However, this first requires that your computer have a Java run-time environment installed. This is commonly referred to as a Java Virtual Machine or JVM for short. Even if your web browser can run Java applets and you have a JVM installed on your computer, the ability to run Java applets might be disabled in your browser (there is usually a configuration option that controls this).
This web site can verify that your web browser is capable of running Java applets in web pages. If your browser is capable, then you can also use this site to see which version of the Java run time environment (JVM) your web browser is using, something that is much harder to do than it should be. There can be multiple JVMs installed in a single operating system instance. If your computer has more than one web browser installed, each web browser can use a different JVM.
For the last five years or so, Microsoft has been including an old Java Virtual Machine in Windows (a version roughly five years old). This causes a problem for Java programmers who have to either limit themselves to Java features as of five years ago or take on the burden of explaining to people how to upgrade their copy of Java to something more current. No doubt, Microsoft would prefer a third alternative, that developers bypass Java altogether. Java allows a computer program to run on many different operating systems, something the vendor of the most popular operating system might see as a threat. For example, the same Java program can execute under all flavors of Windows, Mac OS8, OS9 and OS X, any flavor of Linux or Unix and even an IBM mainframe, without being re-compiled.
| Java Virtual Machines are available from a number of software companies, but you are best off with one from Sun Microsystems. Yahoo has a short list of JVMs, Dmoz has a longer list. Internet Explorer 5 and 6 used to default to using a JVM from Microsoft (no longer). Netscape 7 used a JVM from Sun. Netscape 4.x used a JVM from Netscape. ThinkPads for the last few years (at least) ship with a JVM from IBM. |
Windows users may have seen the term applet describing the things in the Control Panel such as Power Options, Mouse options, Add/Remove Programs, etc. These control panel things (for lack of a better term) have nothing to do with Java. The term "applets" was used to indicate that the Control Panel things are small applications and pre-dates Java.
JavaScript is separate and distinct from Java. Some web pages create JavaScript errors when loading. This is likely due a coding error in the web page being viewed. JavaScript errors have nothing to do with Java at all.
When referring to Java in the context of a web browser running applets (Java programs in a web page), we are really speaking about the Java run-time environment used by the web browser to run the applets. The run-time environment is called a Java Virtual Machine (JVM) by its creator, Sun Microsystems. The folks at the Mozilla project refer to it as the Java Run Time Environment (JRE). Microsoft calls it a VM (for Virtual Machine) probably because they don't want to mention "Java". Don't confuse the "VM" Microsoft refers to with VM products from VMware, Connectix and IBM. These products have nothing to do with Java.
