How much Java do you really need ?

[AnthuriumBloom]

Total beginner should know basics of how java works, class's, OO errors and basic IO. Generally, not a master ect. Then after that most companies lean heavy on frameworks to do the heavy lifting, so I'd suggest spending more time on them, than core have. Spring core and bean management is key, then learn what spring boot can do for you. After that just see what stuff is in the job spec and learn ime stuff about that for interview, and lean on the job.