California Code, Code of Civil Procedure - CCP § 664

When trial by jury has been had, judgment must be entered by the clerk, in conformity to the verdict within 24 hours after the rendition of the verdict, whether or not a motion for judgment notwithstanding the verdict be pending, unless the court order the case to be reserved for argument or further consideration, or grant a stay of proceedings. If the trial has been had by the court, judgment must be entered by the clerk, in conformity to the decision of the court, immediately upon the filing of such decision. In no case is a judgment effectual for any purpose until entered.