how to make nested HashMap in java

Question

i'm trying to put an anonymous hashmap into another hashmap:-

Map<String, Object> requestBody=new HashMap<String, Object>();
requestBody.put("UPSSecurity", new HashMap<String, Object>().put("username","rohan"));
System.out.println(requestBody);

Output is:-

{UPSSecurity=null}

see: http://stackoverflow.com/questions/29242665/java-how-to-adress-a-hashtable-in-a-hashtable/29242857#29242857 — midor, Jul 15 '16 at 10:10
You are calling ```put```, which returns the previous element at that key. Since the map was empty, that is ```null```. — Jorn Vernee, Jul 15 '16 at 10:16

score 5 · Accepted Answer · edited Jul 23 '21 at 12:04

5

Please use this way to define your Nested Hashmap.

Map<String, Object> requestBody=new HashMap<String, Object>();
Map<String,Object> userdetails=new HashMap<String, Object>();
userdetails.put("username","rohan");
requestBody.put("UPSSecurity",userdetails );
System.out.println(requestBody);

Output:

{UPSSecurity={username=rohan}}

edited Jul 23 '21 at 12:04

kohane15

809
12
16

answered Jul 15 '16 at 10:25

Alok Ray

88
6

so if there are 10 nested hashmaps then i have to create 10 local hashmaps – Rohan Dodeja Jul 15 '16 at 10:46
how to extract the data of UPSSecurity – swapnil kambe Apr 03 '20 at 05:58
How to get 10 nested hashmap data – swapnil kambe Apr 03 '20 at 06:37

score 1 · Answer 2 · answered Jan 16 '18 at 10:13

1

You can also do it this way.

Map<String, Object> requestBody=new HashMap<String, Object>();
requestBody.put("UPSSecurity", new HashMap<String, Object>());
requestBody.get("UPSSecurity").put("username","rohan");

answered Jan 16 '18 at 10:13

Bhavin Matreja

88
1
10

how to make nested HashMap in java

2 Answers2