A computer-implemented method, system, and article of manufacture for generating hash codes to identify objects. The method increases variation in object hash codes to reduce conflict between object hash codes and enables them to be added to pinned objects. The method includes: generating a seed value for each heap area and generating the hash code on the basis of address of the object and seed value of the heap area to which the object is allocated. The article of manufacture includes computer readable instructions which, when implemented, cause a computer to perform the steps of the above method. The computer-implemented system includes a processor; and a memory which includes a hash code, an object, a seed value, and a heap area, wherein the processor is configured to perform the steps of the above method.