1. merge 2 sorted Array 2. flatten the array of object type ex: Object[] array = { 1, 2, new Object[]{ 3, 4, new Object[]{ 5 }, 6, 7 } }; o/p: {1,2,3,4,5,6,7} .using stream Api 3. Stock Buy and sell 4.Array with -ve and positive integer.. return pair with max product. 5. LRU cache Impl 6.We have Order class with orderId and OrderTime.. In a function we have startTime and endTime.. we needed to return all the order placed with in that time range[startTime, endTime];