|
Website by Michael Horowitz  |
|
Website by Michael Horowitz |
|
|
| Test the version of Java your browser is using |
Java programs are designed to run in a web page, where they are referred to as applets. Running an applet requires that the computer have a Java run-time environment installed. This was initially referred to as a Java Virtual Machine (JVM) but now the more common term is JRE (Java Runtime Environment).
On Windows and Linux Java comes from Oracle (previously from Sun). On Macs, Java comes from Apple. In October 2010 Apple made it clear they don't like Java (much like their stance on Flash) and will not support it in the future. Microsoft used to maintain their own JRE on Windows but that fell by the wayside long ago.
Apple and Microsoft don't like Java for the same reason, it makes their operating system less important. A Java program can, in theory, run equally well on Windows, OS X and Linux. And, that's just for starters. As long as there is a JRE for an operating sytem, Java programs can run. This opens up other environments too, such as IBM mainframes and Unix.
When Java was created, the touted ability to write a program once and run it anywhere was the cat's meow. Early in the life of Java, JREs were available from many different companies, among them IBM and Netscape, for many different operating systems. But, it all went wrong.
As it played out over the years, Flash beat Java in the marketplace. Flash now serves the same cross platform needs that Java was intended for. I'm not sure exactly why it played out this way, but the differences between JREs from difference sources was mocked as "write once debug everywhere", a takeoff on the initial promise of "write once, run anywhere". Perhaps Flash won out simply because there was only one source (Adobe now, Macromedia initially) for its runtime environment.
No surprise then that Microsoft and Apple don't like Flash either. In October 2010 Apple announced they would no longer pre-install Flash on OS X. Microsoft competes with Flash by offering Silverlight. Java seems to be further hampered, according this October 2010 article at Ars Technica (Java wars: IBM joins OpenJDK as Oracle shuns Apache Harmony) by Oracle/Sun which is standing in the way of an open source Java Runtime Environment.
As for your computer, even if there is a JRE installed, the ability to run Java applets in a browser might be disabled. Both the browser and the Java Control Panel (the Java thingy in the Windows Control Panel) have options to disable Java use by a browser. So too does the Noscript extension for Firefox.
The Version page of this site verifies that your browser is capable of running Java applets in web pages by running a very simple applet that displays the version of Java. The source code for the applet is on the About page.
There can be multiple versions of Java installed on a computer. Somewhere in the lifespan of Java version 6 (I think it was Update 10) Sun added the ability for new versions of Java to remove older versions. However, this didn't go all the way back. That is, very early versions of Java 6 may not be automatically removed, neither are versions of Java 5. So, a computer with more than one web browser can have each browser using a different version of Java, or one browser enabled for Java and another not.
Java got some unwanted publicity in October 2010 when stories appeared in the tech press about bad guys exploiting bugs in older versions of Java to install malicious software. The Version page here not only reports the version of Java a web browser is using, it also has a history of Java releases. For more about the dangers of having an old version of Java installed see my Computerworld blogs
Windows users may find the term applet describing the small applications in the Control Panel (Power Options, Mouse options, Add/Remove Programs, etc.). These control panel applications have nothing to do with Java.
JavaScript is separate and distinct from Java. No relationship at all.