This week's book giveaway is in the OCAJP 8 forum. We're giving away four copies of OCA Java SE 8 Programmer I Study Guide and have Edward Finegan & Robert Liguori on-line! See this thread for details.
why should i go for iterator interface to navigate through the collection.
The main advantage in using an iterator is that it abstracts the collection. Your code is not concerned with the type of collection, nor how is it implemented, you merely use it. And assume that the iterator is written to best traverse the collection -- regardless of whether it is a List or a Set, or whether it is implemented as an array, hashed, or linked.