A simple LRU cache implementation inspired by LeetCode's problem
./gradlew build
./gradlew test
LRUCache<String, String> cache = new LRUCache<>(2 /* capacity */);
cache.put("Hi", "Hi");
cache.put("Bye", "Bye");
cache.put("No", "No"); // deletes "Hi"
cache.get("Hi") // returns null