What are the use cases of LinkedHashMap in Java?

What are the use cases of LinkedHashMap in Java?

LinkedHashMap is useful for maintaining the order of elements while providing fast access. Common use cases include caching, implementing LRU (Least Recently Used) caches, and maintaining insertion order in collections.

Can you explain how it differs from HashMap?

Sure! Unlike HashMap, LinkedHashMap maintains a doubly-linked list of its entries, which preserves the order of insertion. This means that when you iterate over a LinkedHashMap, the elements will be returned in the order they were added.

Are there any performance considerations I should be aware of?

Yes, LinkedHashMap has slightly higher overhead than HashMap due to the additional linked list. However, it provides predictable iteration order, which can be beneficial depending on your use case.

Can you give an example of using LinkedHashMap for caching?

Certainly! You can use LinkedHashMap to implement an LRU cache by overriding the removeEldestEntry method to remove the oldest entry when the cache exceeds a certain size.