A Map in JavaScript is a collection of key-value pairs where each key is unique. It provides an efficient way to associate data, making it easy to retrieve values based on their corresponding keys.

Need to add multiple values to a key in a Java HashMap but can't figure out how to do it? Here are three examples of how to solve the multiple values per key problem in Java.

Take advantage of the SortedDictionary, SortedList, and SortedSet classes in C# to store key-value pairs and sort them based on keys.