Java applets are small Java applications that run inside a web browser window. These applications can do anything from simple database calls on up to managing a persons finances. Since the applets are run in a web browser, they can be run across multiple platforms such as Windows, Mac OS X and Linux. Some mobile browsers also support running Java Applets, if the appropriate software has been installed on the phone by the manufacturer.
Microsoft Internet Explorer runs on computers utilizing the Windows operating system. The newer versions utilize Sun Microsystems Java Virtual Machine (VM). While Microsoft had developed it's own VM, it no longer offers its customers that option. Internet Explorer is the most widely used web browser in the world and offers complete support for Java applets. Internet Explorer is currently available for the Windows operating system.
Apple Safari is a newer web browser, originally developed for the Mac OS and then ported to Windows. It also offers full Java support. Safari uses Sun's Java Virtual Machine. Apple has supported Java Safari has supported Java since Safari's first release. Safari is available on Windows and Mac operating systems users.
Mozilla's Firefox browser has quickly become a very popular web browser. Java is fully supported by Firefox via the Java Plug-in for Firefox. To properly run Java applets you must also install Java 6 Update 15 from Sun Microsystems. Firefox runs on all major desktop platforms.
Opera is another browser that is fully Java capable. It's different from some browsers in that it directly accesses the Java virtual machine, as opposed to accessing it through a plug-in. Opera is available for all major desktop operating systems.
Google's Chrome browser is one of the newest web browsers and was designed to offer a full Java experience. Chrome accesses Java via a plug in. Chrome is available for Windows, Mac and Linux
Several mobile browsers support Java. The mobile edition of Java is called Java Platform, Micro Edition (Java ME). Java ME browsers don't normally offer the full Java experience, and usability will differ from device to device. The mobile virtual machine is known as the K Virtual Machine, and in most cases most be installed on the phone by the manufacturer. Notable exceptions are Apple's IOS devices and Google's Android devices. IOS devices do not run applets. Android offers limited applet support.