Add Learning Java Language eBook (#5966)

* Added HTML5 Canvas Notes for Professionals

* Added Learning Java Language eBook

* Added Rip Tutorials in books/free-programming-books-subjects.md

* Update books/free-programming-books-langs.md
Co-authored-by: NDavid Ordás <3125580+davorpa@users.noreply.github.com>
Co-authored-by: NDavid Ordás <3125580+davorpa@users.noreply.github.com>

books/free-programming-books-langs.md

@@ -987,6 +987,7 @@ That section got so big, we decided to split it into its own file, the [BY SUBJE
 * [Java Programming](https://en.wikibooks.org/wiki/Java_Programming) - Wikibooks
 * [Java Programming for Kids](https://yfain.github.io/Java4Kids/) - Yakov Fain
 * [Java Projects, Second Edition](https://www.packtpub.com/free-ebooks/java-projects-second-edition) - Peter Verhas (Packt account *required*)
+* [Learning Java Language](https://riptutorial.com/Download/java-language.pdf) - Compiled from StackOverflow Documentation (PDF)
 * [Microservices Best Practices for Java](https://www.redbooks.ibm.com/redbooks/pdfs/sg248357.pdf) (PDF)
 * [Object-Oriented Programming in JavaTM Textbook](http://computing.southern.edu/halterman/OOPJ/) - Rick Halterman (PDF per Chapter)
 * [Object Oriented Programming using Java](https://bookboon.com/en/object-oriented-programming-using-java-ebook) - Simon Kendal (PDF) , Bookboon. (email address *requested*, not required)

books/free-programming-books-subjects.md

@@ -71,6 +71,7 @@ Books that cover a specific programming language can be found in the  [BY PROGRA
 * [Papers we love](https://github.com/papers-we-love/papers-we-love)
 * [Programming](https://en.wikibooks.org/wiki/Category%3aComputer_programming) - Wikibooks
 * [Red Gate Books](http://www.red-gate.com/community/books/index)
+* [Rip Tutorials](https://riptutorial.com/ebook)
 * [Stef's Free Online Smalltalk Books](http://stephane.ducasse.free.fr/FreeBooks/)
 * [TechBeamers.com](http://www.techbeamers.com)
 * [TechBooksForFree.com](http://www.techbooksforfree.com)