I can't say this will be particularly useful to what you're trying to do, but the whole EDGE integration capability that supported the legacy Guidewire digital products (the non-Jutro ProducerEngage, etc products) is built on a dependency injection framework. That is tightly linked to the JSON-RPC entry point so it's not intended to be used in a more general sense but if you're looking for an example that's the best one generally available that I'm aware of.

For modern usage where the GWCP Cloud APIs are intended as the primary entry point into the IS applications that example isn't particularly useful or informative. If you can share more information about what problem you're trying to solve the community may have more feedback.