Java is a programming language used in some software programs and by your internet browser for websites that use Java for added functionality. For most users and systems, if you do not have at least Java 7 update 10 installed, you should uninstall all previous versions of Java installed on your system and then install the newest version from www.java.com
Most of Java's current security flaws are being exploited over the internet and through the Java browser plug-in. For the time being and for the greatest security, I suggest that you disable the Java plug-in in any and all web browsers that you use. With the newest version of Java installed on your system but disabled in your browser, this configuration will allow any programs that you have installed on your system that requires Java to continue to function, but will stop attackers from exploiting your browser's plug-in over the internet.
With the newest version of Java installed, it is now possible to disable Java in any browser just by disabling the Java plug-in. But this configuration will not work if any of your favorite websites require Java to run such as some game and chat sites. If you choose to leave the Java plug-in enabled for this reason, just be aware that you are at risk and don't visit websites that you don't explicitly trust.
To disable Java in Internet Explorer: From the toolbar: Tools -> Manage Add-ons -> Disable both Java plug-ins under "Oracle America Inc."
To disable Java in Firefox: From the toolbar: Tools -> Add-ons -> Plugins -> Disable Java Platform
Most other browsers should be configurable in the same manner.