Java
2 resources
A
⬡ Website
Video series
Problem sets & exercises
AP Computer Science in Java - Khan Academy
Covers Java fundamentals through the AP CS curriculum - variables loops arrays OOP and algorithms - with built-in practice at every step.
J
▶ YouTube
Single video
Java in 100 Seconds
Fireship's signature 100-second overview of Java - bytecode the JVM OOP and why it still powers enterprise and Android. Snappy and memorable.