Added Useful Links (#6843)

* Added Useful Link

Added useful links under Java and Python.

* Update free-programming-books-langs.md

* Update free-programming-books-langs.md

books/free-programming-books-langs.md

@@ -1044,6 +1044,7 @@ 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*)
+* [Java Tutorial](https://www.scaler.com/topics/java/) - Scaler Topics
 * [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)
@@ -1948,6 +1949,7 @@ That section got so big, we decided to split it into its own file, the [BY SUBJE
 * [Python Programming](https://upload.wikimedia.org/wikipedia/commons/9/91/Python_Programming.pdf) - Wikibooks (PDF) (2.6)
 * [Python Programming And Numerical Methods: A Guide For Engineers And Scientists](https://pythonnumericalmethods.berkeley.edu/notebooks/Index.html) - Qingkai Kong, Timmy Siauw, Alexandre Bayen (3.7)
 * [Python Tutorial](https://www.tutorialspoint.com/python/) - Tutorials Point (HTML, PDF)
+* [Python Tutorial](https://www.scaler.com/topics/python/) - Scaler Topics
 * [Scipy Lecture Notes](http://scipy-lectures.github.io)
 * [SICP in Python](http://www-inst.eecs.berkeley.edu/~cs61a/sp12/book/) (3.2)
 * [Slither into Python: An introduction to Python for beginners](https://web.archive.org/web/20210411065902/https://www.slitherintopython.com/) (3.7) *(:card_file_box: archived)*