Abstract: A computer system, program product, and method of collecting interned data utilize an interned indicator for an internable data element that indicates whether such a data element is in fact interned within an intern data structure. By maintaining this information, iteration completely through the intern data structure during collection may be avoided, thereby reducing the overhead and improving the efficiency of the collection process. In addition, a computer system, program product, and method of collecting interned data may also determine during a second stage of a collection cycle whether an interned data element, which was determined to be unreachable during a first stage of the collection cycle, has subsequently been accessed through an intern data structure since the beginning of the first stage of the collection cycle.