Data Structure plays very important role in any computing application or software program for productive use of un-structured data. Java has its own implementation of different data structures and that is Collections Framework. It is very important to know what collection to use in what kind of scenario/operation. Selection of wrong collection leads to bad application design or long processing time. Many times, Collections are often misunderstood. Java developers need to understand how Collections work and how they can choose right collection for right problem.This white paper will provide an easy way of identifying right collection in very diagrammatic manner for different Java Collections like Set, Map & List as well as for many of their implementations.