Res judicata in the court of justice case-law: Balancing legal certainty with legality?

Forms of res judicata - Unwritten principle of EU law - National procedural autonomy v. EC supremacy - Revision of decisions v. state liability - Finality of administrative decisions v. judicial decisions - Higher respect for judicial decisions than for administrative decisions - Res judicata not absolute - ECJ itself under demands of legal certainty - Analogy between res judicata rules and rules of direct and indirect effect