Added Java Cheat Sheet (#4884)

free-programming-cheatsheets.md

@@ -5,6 +5,7 @@
 * [Data Science](#data-science)
 * [Git](#git)
 * [HTML / CSS](#html--css)
+* [Java](#Java)
 * [JavaScript](#javascript)
   * [jQuery](#jquery)
   * [Vue.js](#vuejs)
@@ -46,6 +47,11 @@
 * [HTML CheatSheet](https://htmlcheatsheet.com) (HTML)
 
 
+### Java
+
+* [Java](https://programmingwithmosh.com/wp-content/uploads/2019/07/Java-Cheat-Sheet.pdf) (PDF)
+
+
 ### JavaScript
 
 * [JavaScript Cheatsheet](https://www.codecademy.com/learn/introduction-to-javascript/modules/learn-javascript-introduction/cheatsheet) - Codecademy (HTML)