Coupang Java Software Engineer Test interview questions

1. I have a java program in which there are a lot of HashMap/HashTable being used for mapping key-value pairs. Now I want to profile or rather count how many times the get() and put() methods have been called in my program. 2. Given a stream of integers and asked to store N uniques numbers performing insert, search, retrieve in O(1) complexity. If the maximum space reached remove the old data and insert the new data. Perform the above using a data structure. 3. Given a number N. write a program to find the number of prime numbers in the range of 1 to N.