Update README.md

Author: AvinandanBose

README.md

@@ -643,6 +643,11 @@ sequenceDiagram
 </tr>
 </table>  
 
+<ul>
+<li><h3><a href= "https://github.com/AvinandanBose/JavaCollectionFramework/blob/main/TreeSetDemo1.java" > NavigableSet→TreeSet</a></h3></li>
+<li><h3><a href= "https://github.com/AvinandanBose/JavaCollectionFramework/blob/main/TreeSetDemo2.java" > Set→TreeSet</a></h3></li>
+</ul>
+
 <h3> Continuing...: Java TreeSet class implements most of the functions that Hash Set uses as given below: </h3>
 
 <ul>