The federal judge in charge of imposing wide-scale changes to how Google runs its app store said he has no intention of micromanaging the tech giant but warned that Google should get ready to open the floodgates.

"We're going to tear the barriers down. When you have a mountain that's built out of bad conduct, you're going to have to move that mountain," U.S. District Judge James Donato said.

Donato made his remarks during an evidentiary hearing Wednesday in San Francisco to determine the scope of his injunction. During the four-hour proceeding, lawyers for Google and the plaintiff, video game-maker Epic Games, pleaded their cases.