I will list down some problems on the topic of linked lists that are commonly asked in interviews.

Important concepts to revise before trying out the problems:

• Linked List

• Node of a Linked List

• Singly Linked List

• Doubly Linked List

• Inserting and deleting nodes in a Linked List

• Runner technique - There will be more pointers and they will move forward at different speeds.

I will list down some problems on the topic of trees and graphs that are commonly asked in interviews. Please revise topics on tress such as Binary Trees, Binary Search Tree (BST), Balancing a Tree, Full and Complete Trees, Binary Tree Traversals (recursive), Tries, Depth First Search (DFS), Breadth First Search (BFS).

1. FORM Based Authentication - Without Container Template

   1. Create a Dynamic Web Project with a web.xml file; name it as ServletSecurity.

   2. Create a servlet RestrictedServlet with url pattern “/RestrictedServlet” that print “Restricted Servlet” to client.

   3. Create a servlet LoginServlet with url pattern “/LoginServlet” that gets the username and password from client and validate it against a dummy hashmap of username and password.

Data integrity is the process of verifying if data is transmitted without corruption or modification, thus making sure that the data received at the receiver end is in fact the same message sent by the sender.  Confidentiality is the process of maintaining data privacy wherein we secure the communications channel, to make sure the data is not accessed in its original form by a third party by eavesdropping.

Confidentiality and data integrity are related to securing the communications channel.

This is the second part of the demo on Basic and Digest Authentication using Apache Tomcat server. We have already created the setup, did necessary configurations within web.xml and tomcat’s tomcat-users.xml, and finally exported it as a war, deployed it into tomcat and tested the basic and digest authentication.