Question

What is the need of Collection framework in Java since all the data operations(sorting/adding/deleting) are possible with Arrays and moreover array is suitable for memory consumption and performance is also better compared with Collections.

Can anyone point me a real time data oriented example which shows the difference in both(array/Collections) of these implementations.

Answer 1

• Arrays are not resizable.
• Java Collections Framework provides lots of different useful data types, such as linked lists (allows insertion anywhere in constant time), resizeable array lists (like Vector but cooler), red-black trees, hash-based maps (like Hashtable but cooler).
• Java Collections Framework provides abstractions, so you can refer to a list as a List, whether backed by an array list or a linked list; and you can refer to a map/dictionary as a Map, whether backed by a red-black tree or a hashtable.

In other words, Java Collections Framework allows you to use the right data structure, because one size does not fit all.