Can someone share a roadmap to learn Microservices Architecture in Java?

Java, java9+, some database, microframeworks (spring boot, java spark), heroku/aws/azure

The architecture is irrespective the platform or implementation.

There is also no finite microservice architecture, it's about contextually slicing respective source bases and teams based on organizational considerations to achieve higher degrees of efficiency, ownership and return on investment of intellectual capital. Single-bounded context. The architecture will vary org to org, project to project, concern to concern and company to company.

Start here:
Domain-Driven Design: Tackling Complexity in the Heart of Software https://amazon.com/dp/0321125215/...

Read this:
https://martinfowler.com/articles/...

Then immediately watch this:
https://youtu.be/X0tjziAQfNQ

Then read this:
http://shop.oreilly.com/product/...

Then read this:
http://shop.oreilly.com/product/...

Then read this:
http://shop.oreilly.com/product/...

Now think about what you've learned for a month.

Then start evaluating a java stack.

@SortOfTested you're... A goddess of knowledge. Great links.

I just want to add: implement something. Most people learn a shitton of theory without practising.

Theory. Prototyping. Frustration and Enlightment. Praxis.

:)