Why don't the variables in the thread's anonymous class have time to be initialized?

Question

Java

... for this, in line 19, I added an expectation if the player variable did not have time to initialize.
pastebin.com/TbFP6wmy
What is this behavior called? How to deal with it / not step on this rake in the future?
UPD class code:
https://github.com/nikit-cpp/VkCachingPlayer/blob/...
UPD2: it turns out that all class variables that can be accessed from multiple threads should be marked volatile?

Answer 1

It is not so easy to take and work with one variable from several threads.
The main question is what value will the read operation read?
Where to learn more about it:
1. Classics of the genre - Java concurrency in practice. Brian Goetz.
2. Java memory model
pragmatics 3. What is memory model .
3. Java memory model itself (not for the faint of heart)
4. Good post on Habré
5. ...
6. PROFIT!
PS: There are a lot of problems in CustomPlayer and not only with multithreading. Practical advice: do not create threads by hand (see ExecutorService - thread pool), do not leave empty catch blocks (at least write an error to the logger), observejava naming conventions , remove code duplication, love life and not lose heart.

Answer 2

Well, actually, I see this shared variable in the code ...
more code is needed. including the declaration of the class of this object :)