Java

The Java Tutorial

Oracle's tutorials on Java; programmer's guide with hundreds of complete working examples, step-by-step instructions, screenshots, etc.

https://docs.oracle.com/javase/tutorial

IBM developerWorks: Training

Click Tutorials for list of free online tutorials from developerWorks covering a variety of topics. Click Courses for a list of free and fee-based Java technology course materials.

https://www.ibm.com/developerworks/java/training