Methods and systems are provided for expressing one or more associations between source language declarations and implementations in a language neutral fashion. A determination is made as to whether a source language association rule related to a declaration is different from a default association rule for a target runtime. If so, an override association is expressed between the declaration and the implementation, and if not, a default association is expressed. Methods and systems are also provided for interpreting an association between a declaration and an implementation in a runtime system, wherein a determination is made as to whether the association comprises an override association. If so, the association is interpreted according to an override association rule for the runtime system, and if not, the association is interpreted according to a default association rule.