Question

you have learned about linked lists and about the Java Collection Interface. What is a linked list? Why might we use them? What is the purpose of the Java Collection Interface? Your initial post should be at least 200 to 300 words.

Answer 1

Linked List :

Linked lists are linear data structures that hold data in individual objects called nodes. These nodes hold both the data and a reference to the next node in the list.

Linked lists are often used because of their efficient insertion and deletion. They can be used to implement stacks, queues, and other abstract data types.

Example : Head 320 10 360 3 400 9 null 320 360 400

Uses :

1. Image viewer – Previous and next images are linked, hence can be accessed by next and previous button.

2. Previous and next page in web browser – We can access previous and next url searched in web browser by pressing back and next button since, they are linked as linked list.

3. Music Player – Songs in music player are linked to previous and next song. you can play songs either from starting or ending of the list.

4. Time sharing problem - used by the scheduler during the scheduling of the processes in the Operating system.

5. Train coaches are connected with the next and the previous ones.

6. Browser cache which allows to use BACK button.

Purpose of Java Collection Interface :

Collections are like containers that group multiple items in a single unit. For example, a jar of chocolates, list of names, etc.

Collections are used in every programming language and when Java arrived, it also came with few Collection classes – Vector, Stack, Hashtable, Array.

Java 1.2 provided Collections Framework that is the architecture to represent and manipulate Collections in java in a standard way.

- When input size is dynamic.

                        • When data grows and shrinks frequently.

- Collection framework is nothing but the data structure in Java. So we can use its functionality instead of writing too much code.

- The framework had to be high-performance. The implementations for the fundamental collections (dynamic arrays, linked lists, trees, and hashtables) are highly efficient.

- The framework had to allow different types of collections to work in a similar manner and with a high degree of interoperability.

           • Whenever you are required to store heterogeneous data.

           • Extending and/or adapting a collection had to be easy.

Benefits :

Java Collections framework have following benefits:

Reduced Development Effort – It comes with almost all common types of collections and useful methods to iterate and manipulate the data. So we can concentrate more on business logic rather than designing our collection APIs.

Increased Quality – Using core collection classes that are well tested increases our program quality rather than using any home developed data structure.

Reusability and Interoperability

Reduce effort – to learn any new API if we use core collection API classes.