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?

In this excerpt from Answercast #19, I look at Javascript and Java, what might happen if you uninstall them, and how to recover from problems.

Java what?

I want to clear up one misconception from the start: Java and JavaScript are two completely different and unrelated technologies.

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.


JavaScript is basically part of your web browser. It's a programming language that is used to make web pages dynamic. That's a fuzzy word for a lot of the different things that you're seeing on websites these days.

The best example I have are things like Gmail where the entire user interface (or much of the user interface) is actually a JavaScript program that's been downloaded as part of the web page that Google provides when you visit Gmail.

JavaScript is important. It is part of what drives much of the web technologies these days. Modern websites frequently use it.

JavaScript and Malware

Now the problem, of course, is that JavaScript is very powerful and with power comes the potential for misuse.

  • Sometimes, JavaScript can be abused to be a vector for malware.

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.

You may notice that if you've ever commented on Ask Leo!, I require JavaScript to be enabled as one of the methods I use to thwart comment spammers. So if you visit Ask Leo! with JavaScript turned off, you can't comment; but that's the only thing that doesn't really work.


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.

Bugs and vulnerabilities in Java

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.

Do you need it?

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 and reinstalling Java again.

End of Answercast #19 Back to - Audio Segment

Article C5372 - May 21, 2012 « »

Leo Leo A. Notenboom has been playing with computers since he was required to take a programming class in 1976. An 18 year career as a programmer at Microsoft soon followed. After "retiring" in 2001, Leo started Ask Leo! in 2003 as a place for answers to common computer and technical questions. More about Leo.

Not what you needed?

May 22, 2012 8:19 PM

Java is "automatically" downloaded and installed??
That has to be a mis-speak of some sort.

May 23, 2012 1:10 PM

WhistlersMum: When I tell my callers (I work in a tech support call center) that something should happen on the computer without them doing anything directly I usually say "AutoMagically" no one has caught me yet. Seriously tho, when a Java program is started, it checks for the JRE, and will prompt to install or install on it's own if the prompt setting is set to accept

Debra Sexton
September 5, 2012 7:50 AM

I went to to view what I would need to re-install Java, if I uninstall my existing Java, and it looks very confusing. The choices look like Jave EE & GlassFish Server, Java ME, Java Early Access
There is no mention of just Java download.

Sun sold Java to Oracle. Go to instead.
Dennis Teel
September 22, 2012 5:14 AM

so absurd..just how many people that are connecting to the internet would benefit from deleting java from their pc's??how many people 'don't' rely on java every time they connect..a very damn few.most people rely on java to run thir software,surf websites,for images,pictures,the list goes on.who is surfing the net without the java installation? what are they doing,just checking their email and shutting down?while java will upload automatically(not all the time..instead,very often a message will pop up claiming the user's need to have java installed)it would get very tedious to load java or let it auto load every time it's 'needed'// in some cases it would take up most of one's internet time. i'll keep my java installed.the chances of acquiring a virus or hackers due to java being installed isn't as high as what many so called 'professionals' make it out to be. it's one of those 'scares' that some people like to throw out on the internet via a forum or blog article that just isn't as crucial as what the author makes it out to be

You are confusing Java and Javascript. Javascript is used by almost everyone and can't be uninstalled. Java should be installed only if you actually need it - and many people do not. Please see: How do Java and Javascript relate to each other?

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