HashMap is fast and so on along with basics like its stores key and value pairs etc. This shows that person has used HashMap and quite familiar with the functionality it offers, but interview takes a sharp turn from here and next set of follow-up questions gets more detailed about fundamentals involved with HashMap in Java .
Please Refer this Link for more Info:
Map data = new HashMap();
Need to have both "America" and "Africa" as value against key "a". Is there any mechanism to achieve this scenario.