Java Practices with a , a doubly linked list project, and a hash table project. Array: Generate N by N 2d matrix and can rotate it. Doubly Linked List(DLL): Similar structure as the SLL, but can be searched in backward way. Then, the doubly linked list is operated to design Stack and Queue, which inherit the DLL class. Hash Table(HT): Using the automatically generated hashcode as input to hashfunction. HT has general add, remove, get functions as other container class; can calculate the average complexity of successful and unsuccessful search; can display information on blocks formed by contiguousdata or empty cells inside table.