What are the performance characteristics of Java collections?

What are the performance characteristics of Java collections?

Java collections have different performance characteristics based on their implementation. For example, ArrayList offers O(1) time complexity for accessing elements, while LinkedList provides O(n) for access but O(1) for adding/removing elements at the ends.

How does the performance of HashMap compare to TreeMap?

HashMap provides average O(1) time complexity for get and put operations, while TreeMap has O(log n) due to its sorted nature. However, TreeMap maintains order, which can be beneficial depending on your use case.

When should I use a LinkedList instead of an ArrayList?

Use LinkedList when you need frequent insertions and deletions, especially in the middle of the list. ArrayList is better for random access and when the size is mostly fixed.

Are there any performance trade-offs I should be aware of?

Yes, each collection type has trade-offs. For instance, while HashSet offers fast lookups, it doesn't maintain order. Understanding your specific use case is key to choosing the right collection.