The Map interface is a bit different than all the other interfaces in the collections framework, such as Set or List. Unlike them, it works with key-value pairs. If you're thinking of Pair, then let me say no, this is not similar to Pair. A Pair is just a pair of two values combined together while a Map is a collection of key-value pairs.
In a Map, keys are unique and cannot be duplicated, whereas values can be redundant. If you try to add two values with the same key, then the latter one will replace the previous one. Values, on the other hand, can be redundant/duplicate. The main reason behind this behavior is that in Map, items are not stored based on order or anything else, but rather a value is stored and retrieved with respect to its key, so redundant keys will make it impossible to distinguish them from each other and to...