Hash of hashes example in Java

HashOfHashes.java

package test;

import java.util.HashMap;

public class HashOfHashes {
   public static void main(String[] args) {

      //deep's type is a HashMap with String keys. Its values are Hashes with String keys and values
      //Notice how you have to say all that twice, just to be sure :-/
      HashMap<String, HashMap<String, String>> deep = new HashMap<String, HashMap<String, String>>();
      
      HashMap<String, String> hashA = new HashMap<String, String>();
      hashA.put("a", "a1");
      hashA.put("b", "b1");
      deep.put("hash A", hashA);
      
      HashMap<String, String> hashB = new HashMap<String, String>();
      hashB.put("a", "a2");
      hashB.put("b", "b2");
      deep.put("hash B", hashB);
      
      //now the contents of deep are (in JSON):
      //{
      //   "hash A" : {"a": "a1",
      //               "b": "b1"},
      //   "hash B" : {"a": "a2",
      //               "b": "b2"}
      //}
   }
}

thanks