Java8 # Program # Requirement - Unique elements and preserve their insertion order

If you need unique elements and preserve their insertion order...

🧩 LinkedHashSet

✅ Why LinkedHashSet?

• Uniqueness: Like all Set implementations, it does not allow duplicate elements.
• Order preservation: It maintains the insertion order of elements, unlike HashSet which does not guarantee any order.

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🔍 Comparison with Other Sets

Set Type	Allows Duplicates	Maintains Order	Performance
HashSet	❌	❌	Fastest
LinkedHashSet	❌	✅	Slightly slower than HashSet
TreeSet	❌	✅ (Sorted order)	Slower due to sorting

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🧪 Example in Java

Set<String> orderedUniqueSet = new LinkedHashSet<>();
orderedUniqueSet.add("apple");
orderedUniqueSet.add("banana");
orderedUniqueSet.add("apple"); // Duplicate, won't be added
orderedUniqueSet.add("cherry");

System.out.println(orderedUniqueSet); // Output: [apple, banana, cherry]

This is especially useful in microservices where you need deterministic behavior in logs, configs, or event payloads. Want to explore how these fits into a Spring Boot use case or a real-world architecture pattern?