If you have to ask ...
If you have to ask this, you probably don't qualify for any of those requirements.
Rephrase the Context
solid knowledge of Java with
solid knowledge of Jazz Guitar.
You would assume someone with
solid knowledge of Jazz Guitar could perform any Jazz song that were asked to with confidence. They should also be able to demonstrate theoretical understanding of the foundations of Jazz by improvising on the spot. They should be able to hold their own with any other musician in a band with
solid knowledge of Jazz Bass or Drums.
Apply this to a programming language such as Python, could you create a solution to any general problem in idiomatic Python? Could you demonstrate advanced understanding of the aspects of the language that are specific to Python? Can you hold your own in a team consisting of other
solid knowledge of Python developers?
It becomes very clear that what is considered
solid knowledge is subjective to the person asking.
That said, given those requirements you should be able to answer pretty much any general knowledge question about the things in question along with a good number of advanced knowledge questions that would come from extensive experience with the things listed.
I would say a 5 digit reputation, at mininum on stackoverflow.com in any specific language tag from answers and not questions would demonstrate
solid knowledge of that topic.