HI @dubesar
As  I am also JAVA developer and I  learned it from various wherewithal, like from YouTube, Blogs, Java Documentation  and so on.
But in the way , fortunately I got books which helped me in my software development journey in following ways:-
1.   Writing clean code
2.   Effective usage of  OOPS concept
3.   Making easy-to-understand documentation for the projects.
So,  I want to contribute  some books to your open source project to add feathers to it and making it more interesting and resourceful.
**I request you to assign this issue to me.**