An efficient method of sub-typing an object in an object oriented computing environment is provided. In one embodiment, the sub-typing method loads an input object having an object type, whereby an embedded array and a cache are searched for an object sub-typing data structure corresponding to the requested supertype. Any found object sub-typing data structures are associated with the input object. In some embodiments, if the object sub-typing data structure is not initially found, an overflow array is searched and the cache is updated with the object sub-typing data structure when the object sub-typing data structure is included in the overflow array. A system and software product is further provided in other embodiments whereby information associated with a particular object sub-type is obtained.