1. A machine-based method comprising: receiving an application specification comprising one or more algorithms each without necessarily being suitable for concurrent execution on multiple nodes in parallel; grouping one or more different object classes into one or more groups, each group being appropriate for executing the one or more algorithms of the application specification, the executing involving data that is available in objects of the object classes; enabling a user to code an algorithm of the one or more algorithms for one group in a single threaded environment without regard to concurrent execution of the algorithm on multiple nodes in parallel; distributing a copy of the coded algorithm to each of the multiple nodes, without needing additional coding; causing the coded algorithm to be executed on each node in association with at least one instance of a group independently of and in parallel to executing the other copies of the coded algorithm on the other nodes, the instance containing objects of the object classes grouped in the group.