Even though Apple has first removed JAVA and most recently remotely disabled the Java 7 plugin on macs where it was installed via its Xprotect.plist mechanism (in detail described here), there are also a couple of very simple measures you can take yourself to prevent any damage…

1. in your browser disable JAVA – note this step might impact on websites such as online CMS systems, bank websites and xero, if required these websites typically will prompt you to switch Java back on…

Safari > Preferences > Security > untick Enable JAVA

Firefox > Tools > Add-ons Manager > Plugins > disable any JAVA plugins

Chrome > open the following URL chrome://plugins (or right click on this link and choose to open in chrome) > disable any JAVA plugins

2. Run Apple > Software Update and ensure that you install all recent Apple JAVA & Security Updates – unless we have already done this for you.

Please note there are various known problems with updating/disabling JAVA and some mostly older Applications:
Graphisofts ArchiCAD > http://www.archicadwiki.com/Bugs/CannotSavePdfAfterJavaUpdate, http://archicad-talk.graphisoft.com/viewtopic.php?p=196972

For the more technically inclined and if for whatever reason you can not live without JAVA, there are instructions on how to reenable Apples version of JAVA available here,
or you can check and update your JAVA version to the latest version provided by Oracle here