Why do I have a Java folder?

[sojourner]

I've made it a point not to install Java on my Mac. However, I see a /System/Library/Java folder and a /Library/Java folder. Is it okay to just delete them? And how can I ensure that Java is not installed again?

[NaOH]

I think the Java-named folders are installed by default, even if they're empty, sort of like how there's typically folders like ~/Library/Sounds even if you haven't installed sounds (like alerts) in a user folder. In that context, I don't think Java has been installed on your machine, and you'll certainly be prompted for it to ever be delivered to your system. That's what I experienced when Creative Suite requested Java.

[acme.mail.order]

Anything inside /System and /Library should be left completely alone, even empty folders. If you haven't installed Java then there won't be any content, and leaving another empty folder in there won't do any harm. Removing it can cause issues if a program wants to check for a particular file and gets an error it doesn't expect.

[onceagain]

Get a root prompt.

Then:

rm -rf /System/Library/Java
rm -rf /Library/Java
ln -s /dev/null /System/Library/Java
ln -s /dev/null /Library/Java

This will prevent anything from being installed in /System/Library/Java or /Library/Java

[sojourner]

@onceagain, That looks interesting. Could I use the same technique to prevent eSellerate from installing itself on my computer?

[benwiggy]

Deleting the Java folders is unnecessary. Firstly, Java is not some "virus" that you need to fear. As long as it is disabled in your browser, you are clear from any exploits on any vulnerabilities that it may have.

Secondly, nothing -- neither Java nor eSellerate -- is going to install itself unless you authorise it.

Having just set up a brand new Mac, I can confirm that there are some Java folders even before Java is installed. I concur with Acme.mail.order's advice about leaving /System well alone. Removing folders (or linking them to /dev/null) may have unexpected consequences.

[sojourner]

Now that Mountain Lion has the gatekeeper feature, does authorizing software that uses eSellerate automatically authorize eSellerate, or do users get a specific notice before eSellerate installs itself?

[trevor]

My understanding of eSellerate is that it would be installed with the same authorization as the app that requires it. If you somehow preemptively force eSellerate to not work, the app you install will think itself unlicensed, and may not work, or may work in a crippled way, depending on how it's written.

[sojourner]

That would be my understanding and experience as well with pre-Mountain Lion OS. Does it do the same in Mountain Lion?

[trevor]

I don't know, but I doubt that eSellerate is treated as a separate app by Gatekeeper, it's far more likely to be treated as the same app as whatever requires it.

Trevor