A method, system and computer program product for optimally allocating objects in a virtual machine environment implemented on a NUMA computer system. The method includes: obtaining a node identifier; storing the node identifier in a thread; obtaining an object identifier of a lock-target object from a lock thread; writing a lock node identifier into the lock-target object; traversing an object reference graph where the object reference graph contains an object as a graph node, a reference from the first object to a second object as an edge, and a stack allocated to a thread as the root node; determining whether a move-target object contains the lock node identifier; moving the move-target object to a subarea allocated to a lock node if it contains the lock node identifier, and moving the move-target object to the destination of the current traversal target object if the lock node identifier is not found.