Hashmap's values update every time if I put new values & keys in it-CodePudding

So the problem is that if I add a new key&value pair to my hashmap it gets updated ,
right now the key is a number like and ID and the value is a list what countains numbers and
every id should have different list but it's broken for some reason.
So I would like to achieve different list values.
There is the code:

HashMap<Integer,List<Integer>> map22 = new HashMap<>();
int countrrr = 0;
List<Integer> asd = new ArrayList<>();
for (int i = 0; i <50; i  ) {
    asd.add(i);
    if (i % 5 == 0) {
        countrrr  ;
        map22.put(countrrr,asd);
        System.out.println(asd);
        asd.clear();
    }
}
System.out.println(map22);

CodePudding user response：

The source of your problem is that your code currently uses only one List for storing all results (because HashMap.put() doesn't make clones of its arguments.) You need to create a fresh list after storing a result in the HashMap.

Something like this:

HashMap<Integer,List<Integer>> map22 = new HashMap<>();
int countrrr = 0;
List<Integer> asd = new ArrayList<>();
for (int i = 0; i <50; i  ) {
    asd.add(i);
    if (i % 5 == 0) {
        countrrr  ;
        map22.put(countrrr, asd);
        System.out.println(asd);
        asd = new ArrayList<>();
    }
}
System.out.println(map22);