Reddit reviews Java 8 in Action: Lambdas, Streams, and functional-style programming

Questo è un classico anche se un po' datato: https://www.amazon.it/Effective-Java-Joshua-Bloch/dp/0321356683

Ti consiglio di abbinarlo a https://www.amazon.it/Java-Action-Lambdas-functional-style-programming/dp/1617291994 per le ultime novità di java 8 (che sono fondamentali).
Sono in inglese e te ne devi fare una ragione... il 99% del materiale di qualità è in inglese.

P.S. Nè html nè css sono "linguaggi"

Books and when possible building side projects.

List of Java-related books I've found helpful.

Clean Code


Java 8 in Action


Data Structures & Algorithms in Java


Test-Driven Java Development

The last book (Test-Driven Java Development) briefly introduces different testing frameworks for java. It gives you a good start to work off of on your own.


Ninja Edit: I'm also adding two websites that have rather useful examples/diagrams for different design patterns.


DZone


TutorialsPoint

As someone who is a long time but intermittent Java developer myself I'd suggest focusing on Java 8 and in particular how the arrival of lambdas is influence the language and ecosystem. As an experienced OO developer I'd guess most other aspects won't present the same learning curve. Superficially even lambdas can appear as a method to reduce boiler plating, but the implications of this trend toward supporting an increased functional programming style run much much deeper I feel. With that in mind I would suggest either the book Java 8 in Action or Functional Programming in Java.

Java 8 in Action is what we use at work.

Edit: Stupid formatting...