Researchers have found Java-based malware that is capable of infecting Windows, Mac OS X, and Linux systems. The malware exploits a known flaw in Java 7 u21 and earlier for which Oracle released a patch in June 2013. The malware communicates with an Internet relay chat channel that serves as a command-and-control server. The network of computers compromised by this malware is used to launch distributed denial-of-service (DDoS) attacks.
Java-based malware driving DDoS botnet infects Windows, Mac, Linux devices | Ars Technica
Cross-Platform Java bot found | ZDNet