You need to store elements in a collection that guarantees that no duplicates are stored and all elements can be accessed in natural order. Which interface provides that capability?
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java.util.Map
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java.util.Set
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java.util.List
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java.util.Collection
A Set is a collection that cannot contain duplicate elements. While the base Set interface (like HashSet) does not guarantee order, the requirement for 'natural order' specifically implies a SortedSet (e.g., TreeSet). Among the choices, Set is the only interface that fundamentally prohibits duplicates, whereas List allows duplicates and Map represents key-value mappings.
To answer this question, you need to understand the different interfaces provided by Java's java.util package for storing collections of elements.
Option A) java.util.Map - This option is incorrect because a Map does not guarantee that no duplicates are stored. It allows for key-value pairs, where each key must be unique, but the values can be duplicated.
Option B) java.util.Set - This option is correct because a Set interface provides the capability of storing elements in a collection without allowing duplicates. It ensures that every element in the set is unique. Elements in a set are not stored in any particular order, but they can be accessed in a natural order.
Option C) java.util.List - This option is incorrect because a List interface allows duplicate elements to be stored. It maintains the insertion order of elements, which means elements can be accessed in the order they were added.
Option D) java.util.Collection - This option is incorrect because Collection is not a specific interface that provides the capability mentioned in the question. It is a more general interface that provides basic operations for collections, but it does not guarantee uniqueness or ordering.
The correct answer is B) java.util.Set. This option is correct because a Set interface guarantees that no duplicates are stored and allows for accessing elements in a natural order.