This indicates an attack attempt to exploit a remote Code Execution vulnerability in Oracle Java Runtime.
The vulnerability is due to insufficient sanitization of raster parameters when handle images. An attacker can exploit this by tricking an unsuspecting user into visiting a webpage containing a malicious Java applet and execute arbitrary code within the context of the application.
Oracle Java SE 7 Update 15 and earlier
System Compromise: Remote attackers can gain control of vulnerable systems.
Apply patch available from the website.