Sun has released updates including fixes for several security vulnerabilities that affect the Sun Java Runtime Environment.
Full details in the release notes at: http://java.sun.com/javase/6/webnotes/6u15.html
Latest Java version available from: http://www.java.com/en/download/
It is advisable to remove older versions of Java to remove the threat exposure. Uninstall details at: http://www.java.com/en/download/help/5000010800.xml