Difficulty: Easy
Correct Answer: java.util.Set
Explanation:
Introduction / Context:Different collection interfaces in Java define different rules for storage: duplicates, ordering, and key-value mappings.
Given Data / Assumptions:
Concept / Approach:Set interface represents collections with no duplicate elements. SortedSet (e.g., TreeSet) provides natural ordering.
Step-by-Step Reasoning:
Map → stores key-value pairs, not individual elements.List → allows duplicates, preserves insertion order, not natural ordering.Collection → general root interface; does not guarantee uniqueness or order.Why Other Options Are Wrong:Only Set ensures uniqueness; TreeSet (implementation) also provides natural order.
Final Answer:java.util.Set
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