What is Res judicata?
Section 11 C.P.C. contains the principles of res judicata or the rule of collusiveness of judgment, as to the points decided either of fact, or of law, or of fact and law, in every subsequent suit between the same parties. Section 11 provides that once the matter is finally decided by a competent court, no party can be permitted to re-open it in subsequent litigation. In the absence of such rule there will be no end to litigation and the parties would be put to constant trouble, harassment and expenses. This doctrine has been accepted in all civilized legal systems.