Why, within the collections hierarchy, does map not implement the collections interface like set, list and queue do?
e.g in this diagram:
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This got answered already couple of times. I.e. here: http://stackoverflow.com/questions/2651819/why-doesnt-java-map-extends-collection – stolzem May 11 '14 at 21:39
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Because unlike Lists and Sets, they're built on key-value pairs. The collection interface only has methods to interact with a unique object at a time, not a key-value pair.
Alexandre FILLATRE
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