1. A method for incrementally unloading classes using a regionbased garbage collector, the method comprising: maintaining, by at least one processor, a remembered set for a class set, the remembered set indicating whether instances of the class set are contained in one or more regions in memory, and in which regions in memory the instances are contained, wherein the remembered set of each class set transitions between a plurality of representations based on an established policy, the representations comprising: (1) an “immediate” representation storing pointers to specific regions in memory where instances of the class set are contained; and (2) a “bit vector” representation comprising a bit for each region in memory that indicates whether at least one instance of the class set is contained in the corresponding region; causing the remembered set to transition from the “immediate” representation to the “bit vector” representation upon determining that a number of regions that contain instances of the class set exceed a number of pointers that can be stored by the “immediate” representation; upon performing an incremental garbage collection process for a subset of the regions in memory, examining the remembered set to determine whether the class set includes instances in regions outside of the subset; and identifying the class set as “live” in the event the remembered set indicates that the class set includes instances in regions outside of the subset.