how to traverse data in linked list in forward and backword direction , write code and algo how to delete node from linked list, write code and algo how to install your project in your system program for an array where keep all 0'z at begning positions and all 1's at last positions why we use interface and abstract class Design patterns internal working of hash map difference between equals and == overloading and overridding Write database query to pring emp name and their manager name from one single table