Java webscraping handbook (#3567)

* Add Java Web Scraping handbook

* Remove trailing '/' on Java Web Scraping handbook

free-programming-books.md

@@ -1504,6 +1504,7 @@ Kerridge (PDF) (email address *requested*, not required)
 * [The Java EE6 Tutorial](https://docs.oracle.com/javaee/6/tutorial/doc/javaeetutorial6.pdf) (PDF)
 * [The Java EE7 Tutorial](https://docs.oracle.com/javaee/7/JEETT.pdf) - Eric Jendrock, et al (PDF)
 * [The Java Tutorials](https://docs.oracle.com/javase/tutorial/index.html)
+* [The Java Web Scraping Handbook](https://www.scrapingbee.com/java-webscraping-book) - Kevin Sahin (PDF, HTML)
 * [Think Java: How to Think Like a Computer Scientist](http://greenteapress.com/thinkapjava/) - Allen B. Downey and Chris Mayfield
 * [Welcome to Java for Python Programmers](https://runestone.academy/runestone/books/published/java4python/index.html) - Brad Miller
 * [Welcome to the Java Workshop (2006)](http://javaworkshop.sourceforge.net) - Trevor Miller