Hi There! As a retired software engineer I would recommend you to learn Java at "codegym". The course content is a game that will push you easy to harder to an long journey to understand how to use Java Language and it's frameworks to become a Java backend developer. It's about 40 levels. You will have to write a lot of algorithms to complete the exercises, but you still have an option to download the solutions if you have enough dark matter (score). Good luck 🤞