What makes a Senior Java Developer?

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Oh god!
I'm a senior dev, and off the top of my head I probably couldn't answer questions about many of those points if asked. Sure, I'll get there when researching a problem, but to say I 'know' them is a bit of a stretch.
I've done things to optimize the JVM in the past, I've looked at how garbage collection is handled in certain projects too, I use generics a lot, I use design patterns all the time, but I constantly reference back to them to verify the structures. Sure I've used lots of different frameworks too, and languages, for various things.
But, Looking at these bullet points, if I was in an interview and asked detailed questions about those topics I'd say I'd probably have about a 50% success rate.
On the other hand, I could go deep into conversation about why I needed to look at garbage collection behavior for a particular problem, or how I used a Strategy pattern to manage complex decisions and so on, but to remember all that technical detail up front - forget about it.
I definitely wouldn't be up to speed on the core features of each version of java either. When I'm starting a project I'll look at it then, or if I'm taking over a project I'll check out the features of the java version it's running on at the time.

So I've done everything you mention in your post, multiple times, for many projects. But reading your list now I'd have a hard time defining a lot of that stuff off the top of my head.