How do you sort alphanumeric key of a map OR Sort map by key in java?

Problem statement:
How do you sort alphanumeric key of a map ?

1. import java.util.HashMap;
2. import java.util.Map;
3. import java.util.Set;
4. import java.util.TreeMap;
5. public class SortAlphanumericKeyInMap {
6.     public static void main(String[] args) {
7.         Map<String, String> map = new HashMap<>();
8.         map.put("A1BB", "1");
9.         map.put("A2CC", "2");
10.         map.put("A2AA", "2");
11.         map.put("B1AA", "7");
12.         Map<String, String> treeMap = new TreeMap<>(map);
13.         Set<String> keys = treeMap.keySet();
14.         for (String key : keys) {
15.             System.out.println(key);
16.         }
17.     }
18. }

Output:

A1BB

A2AA

A2CC

B1AA