This issue pertains specifically to Minecraft, but it is affecting all Java programs that run on my computer.
It would seem that something is forcibly setting a _JAV
This error occurs actually when you run an android application after compiling a java program. Eclipse uses java's compiler to execute android application. So run your android application as an android application. Just right click on project and click on run as->android application instead of run configurations.
You probably have a Razer device. Their god-forsaken software secretly adds _JAVA_OPTIONS, but only when launching games, so you won't even see it from CMD. Ideally uninstall the software, and maybe splash some holy water on your PC. Failing that, you can probably get by with shutting down Synapse and restarting minecraft.exe
Found (eventually) here: http://www.minecraftforum.net/forums/support/unmodified-minecraft-client/2183431-_java_options-picked-up-without-existing#reply