I have been a professional developer for almost 20 years and I have never been a manager by choice, but I conduct lots of interviews where I get to make the "no go" decision on applicants. In other words, I am never the final say whether you do get hired but if I tell a manager, I don't think you should get hired, you won't.
I would never hire you for a senior developer position.
1. Your communication skills suck. A good developer should be able to describe the problem and the solution in an easily understandable manner. You use way too many acronyms.
2. You admit that your knowledge of CS is "unstructured". If you think you have picked up the "craft" in a short period of time, you are not self-aware enough to know what you don't know. When I interview a "web developer". I want someone who knows front-end, web services or the server side framework in question, how to properly layer the stack, unit testing, databases, etc. Do you know that?
3. Why would I hire you if you don't know the language you are being hired for? Java is not a new flash in the pan language. It's been around and popular for 20 years.
4. " Rarely a developer gets exposed to a single technology for a substantial period to learn it inside-out. " This very statement shows an extreme lack of technical maturity. I know plenty of developers that know their chosen stack inside and out. If you have been jumping around from technology to technology every six months it shows a lack of focus.
4. Of course I am going to "grill you on CS theory". If you understand CS theory well, I would have more confidence that you could pick up a language/technology fast. Theory doesn't change that often. If I can ask you about MVC and you know the theory behind it in Java well, I would expect you to pick up Angular fast.
5. " So, what matter's today? Knowledge on a particular technology or re-usable engineering skills ?" Both. I want you to be able to demonstrate that you have used the latest technologies either in your job or side projects and that you have spent time studying language agnostic concepts like project management, design patterns, etc. I want to make sure that I am working with someone that is an aggressive learner.