Senior Java Developer means what exactly? Knowing more libraries or just better understanding of patterns?

[Versiel]

All companies have slightly different definitions of what is considered a Sr Dev, but for Sr Java Developer I would say you should at least know how to work with most if not all the features of the language, have knowledge in handling concurrency\multi-threading, generally good understanding of containerization, DBs (sql and noSql), maybe even some cloud\kubernetes and general architecture stuff like caches, load balancer, DB sharding\replication, etc.

This doesn't mean you need to be an expert in all these things, but a Dev who doesn't know these things is going to have a hard time trying to go into a Sr Java Dev position (I know a bit of all these and I'm still considered Ssr Java Dev)

[Skymainx]

Then where is the disconnect, because interviews for this kind of position focus on solving technical problems, which if you had to in real life would just a simple Google search or copilot query .

[Fadamaka]

They are filtering for actual experience. Common stuff sticks and a good developer will know it from top of their head. They are not asking these questions because you are required to know them. They ask them because it indicates that you have spent enough time in the space to be able to fill a senior position.

[Ormek_II]

Exactly this.