• Before following these steps, run Software Update and make sure you have all the latest updates installed. Additionally, if you open any applications that ask you to install a Java Runtime Environment (or JRE) it means you do not currently have Java installed.
• To disable Java on browsers other than Safari go to the website of their developer and see if they offer instructions.
Mac OS 10.4 and 10.5:
Open Safari. In the main menu click on Safari and open Preferences.
Now select the Security tab and uncheck Enable Java.
Mac OS 10.6:
Follow the same instructions for Safari as described above or;
In your Applications folder > Utilities, you can find the Java Preferences application. Open this and uncheck “Enable applet plug-in and Web Start applications”. Also uncheck the boxes next to all “Java SE #” in the list below.
OS X 10.7 and 10.8:
If you are running the latest version the Java Preferences application i mentioned above will no longer be present, Apple has removed it with a software update. This does not mean Java is gone or disabled. If you do still have the application in your Utilities folder then follow the steps as described for 10.6 to disable Java.
As for Safari, disable Java as described for 10.5 above.
Gatekeeper in 10.8 will also automatically disable Java versions that are deemed unsafe by Apple.
If the Java Preferences application can not be found but you do want to control Java, make sure it’s up to date and disabled then download the latest version/update from the Oracle website. As Java is no longer a part of OS X, any installations or modifications of Java have to be done through a System Preferences panel that is only present after you install Java yourself.
Some people need Java, others (like me) want it installed in case they need it, for testing and/or just to make sure it is disabled properly through the settings. If you want/need Java:
Click here to go to the Oracle website and download the latest version.
Once installed open your System Preferences, you’ll see a Java icon in the bottom row. Click on it and the Java Control Panel will open giving you access to regulate anything Java on your system. First click the Update tab, check for updates and if any are available install them. Also make sure the “Check for Updates Automatically” checkbox is on. Next click on the Security tab. If Java is on, set the security level to High or Very High and click Apply. (test your applications and websites that require Java to see if they still function, adjust the security level if needed). If you don’t need Java and just have this Control Panel installed to check up on Java, control it or disable it, uncheck the “Enable Java content in the browser” box.
Another option, if you do not need or want anything to do with Java, is to completely get rid of it. This is not an easy task though and will require some fiddling around in the Terminal. A good place to start is by deleting the Runtime Environment (that mini Operating System i mentioned earlier). This can be found on your hard drive under System/Library/Java/JavaVirtualMachines. Once you are there, delete the 1.6.0.jdk (your numbers may be different) file. Without it’s runtime, Java can’t function. While this leaves some random Java files on your system they are harmless, don’t take up any space and can’t aid in installing malware.
There are the options available to you. Keep in mind that if you choose to keep Java, even if it is disabled in OS X versions prior to OS X 10.8.3, you may be at risk and a good antivirus application is recommended.