You don't need to remove it completely. It's deeply embedded in the system and removing it is no simple task. But if you open Java Preferences.app in Utilities, you can disable the Java Runtime Environment, which is where all the open vulnerabilities are. Just uncheck all three boxes and you're done. You can also disable the Java plugin in the browser.
The other poster is incorrect. You absolutely may entirely remove Java from your system.
Uninstall Oracle Java 7
Uninstalling Oracle Java only involves deleting the Java Plugin file JavaAppletPlugin.plugin.
Note: To uninstall Java 7, you must have Administrator privileges.
- Click on the Finder icon located in your dock
- Click on Applications tab on the sidebar
- In the Search box enter JavaAppletPlugin.plugin
- This will find the JavaAppletPlugin.plugin file
- Right click on JavaAppletPlugin.plugin and select Move to Trash
From there, empty your trash. As a further measure for security, open up Safari and follow this short list of instructions;
Safari > Preferences > Security > Uncheck "Enable Java"
Macology's reply is incorrect. While his instructions are the official Oracle instructions they merely delete the JavaApplePlugin. That's not an uninstall. Given (1) the ungoing security problems with Java in the browser and (2) that java -version does not report what you expect (Java Version 7 Update X), I'd love to find full uninstlall directions. Oh... want to make sure you're secure, turn it back on in the browsers. Uhm... right.
After trying various things suggested, here's what I've found (basically a summary of the above with a few additional details)
You can disable it in the browser (presumably all) by going to System Preferences > Java
Deleting the JavaAppletPlugin (another approach above) may do something similar or may block more Java items from running
A full uninstall is much more complicated (e.g. on my system, you're removing around 4k items). BUT, when I did a test (by adding .disabled on the end of several key java folders) --while I didn't find OS X complaining-- I immediately found programs that wouldn't function. The most surprising is Creative Suite. Starting Photoshop (I think) resulted in it saving java is required. My experiment in being Java free was very very brief.
FWIW, the way I'm managing things is that I keep Java turned off in all the browsers (Chrome and Safari) I use regularly. Safari is my, dag nab it, I have to go site X that uses Flash|Java|Dumb plugin browser.
AND then, I only use that browser when I need to go to one of those sites. There's still some security risk but my exposure is a lot lower. The why Safari isn't really relevent beyond saying I picked the browser I didn't need for other stuff.
Finally (and I wish I could remember where I found this), there are some pretty hardcore security settings possible. Whereve I found it, I've got Java asking permission every time a Java applet tries to run in the browser. Slightly annoying but not likely a rogue applet is going to run without my knowledge.
Hopefullly that adds more to the light everyone has shed on the subject.
Both Macology and coyote4til7 are correct.
Macology is talking about the Oracle JRE7 installation, which can be removed exactly as he describes.
coyote4til7 is talking about the Apple supplied java6 installation, which is optional, but once it is installed, cannot be removed.
They are both different beasts.
Your browser will use JRE7, if it is installed as Apple has disabled the web plugin for java6.
Do not attempt to remove java6 as just about every software that uses java on OS X requires java6 to be installed and removing it will break those programs. Different java versions are not necessarely backwards compatible. If you java6 installed, you also have programs that depend on it installed as well.