Hermetic high density interconnected electronic system or other body

A body is hermetically sealed by electroplating a hermetic layer over the exterior surface of the body. A high density interconnect structure (100) is hermetically sealed by forming a continuous metal layer (144) over the outermost dielectric layer (160) of the multilayer interconnect structure and by disposing that continuous metal layer in a hermetically sealing relation to the substrate (112) of the high density interconnect structure. A variety of techniques may be used for providing electrical feedthroughs (118) between the interior and exterior of the hermetic enclosure as may a pseudo-hermetic enclosure in those situations where true hermeticity is not required.