California Codes, Code of Civil Procedure - CCP, Part 3 — Of Special Proceedings of a Civil Nature, Title 3 — Of Summary Proceedings, Chapter 4 — Summary Proceedings for Obtaining Possession of Real Property in Certain Cases, Section 1164

No person other than the tenant of the premises and subtenant, if there be one, in the actual occupation of the premises when the complaint is filed, need be made parties defendant in the proceeding, nor shall any proceeding abate, nor the plaintiff be nonsuited for the nonjoinder of any person who might have been made party defendant, but when it appears that any of the parties served with process, or appearing in the proceeding, are guilty of the offense charged, judgment must be rendered against him or her. In case a defendant has become a subtenant of the premises in controversy, after the service of the notice provided for by subdivision 2 of Section 1161 of this code, upon the tenant of the premises, the fact that such notice was not served on each subtenant shall constitute no defense to the action. All persons who enter the premises under the tenant, after the commencement of the suit, shall be bound by the judgment, the same as if he or they had been made party to the action.