It means that the GC always be able to collect all free memory. This is as opposed to a conservative GC that may fail to collect memory if there is an object th

It means that the GC always be able to collect all free memory. This is as opposed to a conservative GC that may fail to collect memory if there is an object that looks like it could be a pointer to it, but isn't. See: http://en.wikipedia.org/wiki/Garbage_collection_%28computer_science%29#Precise_vs._conservative_and_internal_pointers http://en.wikipedia.org/wiki/Garbage_collection_%28computer_...