Patent ID: 7441252

Claim:
A cache control unit comprising an internal computing system that comprises executable program instructions and a processor for executing the program instructions, wherein the cache control unit controls the cache of instances of database objects that are referred to by an application, the cache control unit comprising the following components implemented in the internal computing system: an instance request reception device that receives access requests for an instance of an object or a class from an application; an instance creating device that creates, in a virtual machine that is separate from the cache control unit, an instance of the object or the class in the case that the instance of the requested object or class does not exist; a counter creating device that creates a counter that is associated with the instance of the object or the class when the instance creating device creates the instance of the object or the class; a reference setting device that creates, in the virtual machine, an instance of a reference setting class, sets the reference that refers to the instance of the requested object or class and sends the result to the application, and increments by 1 the counter associated with the instance of the object or the class; and an instance release device that receives a release notification for an instance of the reference setting class, decrements by 1 the counter associated with the instance of the object or the class referred to by the instance of the reference setting class, and in the case that the counter has reached 0, releases the instance of the object or the class that is associated with the counter.