Collection Vs Array Performance wise

Question

Could you please let me know Performance wise why Array is better than Collection?

Answer 1

It is not. It will actually depend on the use you make of your container.

Some algorithms may run in O(n) on an array and in O(1) on another collection type (which implements the Collection interface).

• Think about removal of an item for instance. In that case, the array, even if a native type, would perform slower than the linked list and its method calls (which could be inlined anyway on some VMs): it runs in O(n) VS O(1) for a linked list
• Think about searching an element. It runs in 0(n) for an array VS O(log n) for a tree.

Some Collection implementations use an array to store their elements (ArrayList I think) so in that case performance will not be significantly different.

You should spend time on optimizing your algorithm (and make use of the various collection types available) instead of worrying of the pros/cons of an array VS Collection.