Can you name different approaches to implementing the Map interface in Java?

In Java, the Map interface is implemented by different classes, each suitable for different tasks:

• HashMap — the most popular implementation, stores key-value pairs without order, provides fast access (O(1) on average).
• LinkedHashMap — extends HashMap, maintains insertion order.
• TreeMap — implements NavigableMap interface, stores elements in sorted order by key (uses a red-black tree).
• Hashtable — outdated synchronized implementation, now often replaced by ConcurrentHashMap.
• ConcurrentHashMap — thread-safe implementation for multi-threaded environments, without locking the entire map.

Example of using HashMap:

Map<String, Integer> map = new HashMap<>();
map.put("apple", 3);
map.put("banana", 5);
System.out.println(map.get("apple")); // 3