Netflix/zuul ? reverse-engineered prompt

Build me a Java based gateway that sits in front of my backend services and acts as the main entry point for all requests. It should handle dynamic routing so traffic gets sent to the right place, while also adding monitoring, resiliency against failures, security checks, and the ability to plug in custom filters that can inspect or change requests and responses on the fly.

Make it extensible like an L7 application gateway with a solid core, some processor modules for the filters, and a sample app that shows how to set it up and run it. Use Gradle to wire everything together so it builds cleanly and I can try it out right away. Feel free to look up current docs on these kinds of proxies if you need ideas.