Method and apparatus for distinguishing reachable objects and non-reachable objects in an object-based application

A method for distinguishing, within a set of objects, reachable objects and not-reachable objects in an object-based application in a system with a volatile memory and a non-volatile memory, said object-based application operating in said non-volatile memory on said objects, wherein at least one of the objects is a root object, said method comprising the steps of:

• determining, for each of the root objects, which of the objects are reachable from said root object;
• writing, for each of the reachable objects, a positive reachability information into said volatile memory;
• and
• marking the objects, for which no positive reachability information is present in said volatile memory, in said non-volatile memory as reusable memory.