List> replacing previous hashmap values

Question

Okay so I've done some research on this and am stuck. I understand now that the list just holds pointers to the hashmap so I end up with 5 pointers to the same value. I cannot for the life of me think of any way to get around this problem. How can i store the values and keep them? I tried using String.valueOf() but that is a pointer as well apparently.

List<HashMap<String,String>> tbcPackages = new ArrayList<HashMap<String,String>>();

JSONObject g = new JSONObject();

for(int i = 0; i <5 ; i++){

    g.clear();

    System.out.println("clear? : " + g);

    g.put("test", i);

    tbcPackages.add(g); 

    System.out.println(tbcPackages);

}

Put `JSONObject g = new JSONObject();` in the loop – Zachary Feb 15 '18 at 23:40 — Zachary, Feb 15 '18 at 23:40
Creatre a **`new JSONObject`** each iteration. – Boris the Spider Feb 15 '18 at 23:41 — Boris the Spider, Feb 15 '18 at 23:41

score 2 · Accepted Answer · edited Feb 16 '18 at 00:01

The problem occurs because you are using same object "JSONObject g". At every iteration of loop, create a new object. The modified code given below:

List<HashMap<String,String>> tbcPackages = new 
ArrayList<HashMap<String,String>>();

for(int i = 0; i <5 ; i++){
  JSONObject g = new JSONObject();
  g.clear();

  System.out.println("clear? : " + g);

  g.put("test", i);

  tbcPackages.add(g); 
  System.out.println(tbcPackages);
}

List> replacing previous hashmap values

1 Answers1