A malware researcher with Microsoft recently released a report indicating that there has been a large increase in the number of network attacks that exploit a vulnerability in Java. Although Adobe's PDF vulnerabilities have received a lot of press, this report says there were six million attacks against Java during 2010 Q3, and only around 100,000 against PDF documents.
The good news is that there are patches available for the three main Java vulnerabilities that are targeted by the attacks, so ensuring that the updates are installed will protect your systems against most of the threat. Java, like Adobe Reader, is installed on most computers and so is a favorite target for attackers.
Read more here: