Helping people with computers... one answer at a time.
When we say "Java," it can be two completely different things. First, we have to decide which you are talking about.
I'm using a laptop PC with Windows Home Premium 64-bit and my concern lies with Java. Just how important is it to have Java on my PC? If I uninstall it, what will happen? If I can uninstall, how do I do it? And what I should have asked first is what is Java?
I know that many people tend to refer to one, thinking that they are referring to the other. For the purpose of this discussion, I'll probably end up discussing both.
That's one of the reasons the tool called 'No Script' exists for Firefox. It allows you to choose whether or not scripting should be allowed on a website-per-website basis.
Java, on the other hand, is a programming language. It is also often used by websites, but it is not part of your browser. It's not something that just naturally comes with IE, or Firefox, or Chrome.
When you need Java, it is typically automatically downloaded and installed.
So, for example, I happen to use GoToWebinar for my monthly webinars. Both the production side (my side) and the client side (the side that you would use to view a GoToMeeting or a Webinar) is a Java application.
That Java application is downloaded when you visit the GoToMeeting website and it is then run on your computer as, essentially, a standalone program.
What you end up having on your computer is called a Java virtual machine. Unrelated to the virtual machine technologies that I've talked about before, the Java virtual machine is this little sandboxed environment that allows Java programs to (presumably) act safely and not cause problems with other software.
Unfortunately, once again, there are occasional bugs and vulnerabilities in the Java virtual machine. That's why it is (typically continually...) updated by the folks at Sun who produced it in the first place.
The answer to your question, "Do you need it?" is, "I honestly don't know."
It depends on what software you run. Software needs it. Some programs are built on Java. If you were to uninstall Java (which you absolutely can do), then those programs would either not work until you reinstalled it or they would automatically reinstall it the next time you tried to use them.
The typical advice when it comes to Java (and this is actually true for software in general) is: if you're not using it, don't have it installed. There's really no point.
If you don't need Java... remember those vulnerabilities I talked about? There are malicious web pages out there that actually include malicious Java programs. If you were to visit them, they would download and run in Java on your machine and potentially take advantage of some of those vulnerabilities.
If you don't have Java on your machine, then you don't have those vulnerabilities. If you have Java on your machine because you require it for some software that you're running (like say, GoTo Meeting), then keep it up to date.
But, that's all it really is. It's another programming language; it's another approach to implementing software that some programs use.
It's very popular because it tends to be cross-platformed. In other words, a program can be written once and run on Windows, and Apple, and other places, with either no or minimal modification. It's one of the draws of Java and one of the reasons you'll see Java as a fairly popular application-creation software in certain circles.
But ultimately, uninstall it and see what happens. Chances are nothing will break. If something does break, it's a simply matter of going to Sun.com and reinstalling Java again.
End of Answercast #19 Back to - Audio Segment