LinkedHashMap vs TreeMap | Generated by AI

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Great question! Both LinkedHashMap and TreeMap are implementations of the Map interface in Java, but they have different ordering strategies and use different underlying data structures.

🌳 TreeMap

• Ordering: Sorted by natural order of the keys (or by a custom Comparator if provided).
• Data Structure: Backed by a Red-Black Tree (a type of self-balancing binary search tree).
• Performance:
  • O(log n) for get/put/remove
  • Sorted order maintained at all times
• Use Case: When you need sorted keys.

🔗 LinkedHashMap

• Ordering: Maintains insertion order (or optionally access order if configured that way).
• Data Structure: Backed by a hash table + linked list.
• Performance:
  • O(1) for get/put/remove (like HashMap)
  • Slightly more memory overhead due to the linked list
• Use Case: When you care about the order in which entries were added.

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✅ Iterator Order

Yes, their iterator order will be different:

Map Type	Iterator Order
TreeMap	Sorted by keys
LinkedHashMap	Insertion order (or access order)

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🔍 Example

Map<String, Integer> treeMap = new TreeMap<>();
Map<String, Integer> linkedMap = new LinkedHashMap<>();

treeMap.put("banana", 2);
treeMap.put("apple", 3);
treeMap.put("cherry", 1);

linkedMap.put("banana", 2);
linkedMap.put("apple", 3);
linkedMap.put("cherry", 1);

System.out.println("TreeMap:");
for (String key : treeMap.keySet()) {
    System.out.println(key);
}

System.out.println("LinkedHashMap:");
for (String key : linkedMap.keySet()) {
    System.out.println(key);
}

Output:

TreeMap:
apple
banana
cherry

LinkedHashMap:
banana
apple
cherry

Let me know if you want a breakdown of performance or memory usage in more detail.

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