I said "utilizing hyperspace." My hypothetical idea was that it would shunt matter or energy through hyperspace into the core of the target star, without having to figure out a way to move the whole planet. It could even keep you fairly well hidden - as most devices that could track that big a of hyperspace disturbance would be destroyed with the rest of the system.
Of course, this is really all moot, but to me, it makes more sense than what we saw in the film:
The slowly advancing red beam that travels across the galaxy for everyone in between to see. Was that traveling through hyperspace? Was it so much energy that it was actually visible, despite traveling through hyperspace? Didn't they try to explain why everyone could see it with some crap about it being so strong that it damaged Space/Time?
So Starkiller uses the matter from its sun to fire the weapon. We see it fire once and attempt a second time. Does it drain the entire supply star, or just the outer layer? The inside of a star is glowy, too... It's daytime on SK Base when they destroy the Hosnian system - so why does it go dark when they attempt to destroy the Resistance base? Did they suck up one star, then move the whole planet to another system before firing at Hosnian?
Getting back on topic, I hope the future of Star Wars includes a LITTLE more thought into how things could work before committing them to film.