The previous serious incidence was brought to light only last August, as reported by DCT here: https://davescomputertips.com/2012/08/java-zero-day-exploit-expected-to-spread/
It’s fairly apparent that Java is a minefield of vulnerabilities just waiting to be exploited. So much so that DCT has previously advised readers that they should “Junk their Java” – https://davescomputertips.com/2011/11/you-should-junk-your-java/
The good news is that Oracle has moved outside its normally rigid update cycle and released an update to fix this latest vulnerability – specifically pertaining to Java 7. If you cannot live without Java, we strongly advise you download this latest version as soon as possible.
Available from Oracle’s web site here: http://www.oracle.com/technetwork/java/javase/downloads/index.html
Reports since that version was released are that not all of the security holes being exploited have been patched and so that version has itself been the subject of vulnerability reports with the recommendation that you uninstall it if you don’t need it or at least disable it in the browser (where it is almost never needed).