Canon 1642

Can. 1642 §1. A res iudicata possesses the stability of law and cannot be challenged directly except according to the norm of can. 1645 §1.

Can. 1642 §2. It establishes the rights between the parties and permits an action for execution and an exception of res iudicata which the judge can also declare ex officio in order to prevent a new introduction of the same case.