What specific implementations of collection interfaces have you used in your projects?

In Java projects, I often used the following implementations of collection interfaces:

• List: ArrayList for dynamic arrays with quick access by index, LinkedList when fast insertion/deletion in the middle of the list is needed.
• Set: HashSet for storing unique elements with quick access, LinkedHashSet if insertion order is important, TreeSet for sorted sets.
• Map: HashMap for associative arrays with quick access, LinkedHashMap to preserve insertion order, TreeMap for sorted key-value mappings.

Example of using HashMap:

Map<String, Integer> wordCount = new HashMap<>();
wordCount.put("apple", 3);
wordCount.put("banana", 2);
int count = wordCount.getOrDefault("apple", 0);