I'm a bit confused about architectural choices for the java/web-applications world.

The background is I have a system with certain hardware components (that introduce system immanent active behavior) and a configuration database for system meta and HW-components configuration data (these are even usually self contained, since the HW-components persist configuration data anyway).
For realization of the configuration/status data exchange protocol with the HW-components we have chosen the Google Protobuf format, which works well for the directly wired communication with these components.

Now we want to develop an abstract model (domain model) for those HW-components and I have the feeling that a plain Java class model would fit best for this (c++ implementation seems to have too much implementation/integration overhead with viable language-bridge interfaces).

Google Protobuf message definitions could still serve well to describe DTO objects used to interact with a domain model API. But integrating Google Protobuf messages client side for e.g. data binding in the current view doesn't seem to be a good choice. I'm thinking about some extra serialization features, e.g. for JSON based data exchange with the views/controllers.
Most lightweight solutions seem to involve a python based presentation layer using JSON based data transfer (I'm at least not sure to be fully informed about this).

Is there some lightweight (applicable for a limited ARM Linux platform) framework available, supporting such architecture to realize a web-application?