This is regarding the usage of subList method in an ArrayList.
Consider I am having an array as below:-
int[] prices = {71,11,65,99,21,82};
I am converting the above array to arrayList as below:-
List<Integer> priceList = Arrays.stream(prices).boxed().collect(Collectors.toList());
Now, I want to retrieve the elements from position 3 till end and I apply the sublist as follows:-
priceList.subList(3, priceList.size());
for(Integer price: priceList) {
System.out.println(price);
}
But I am still getting the entire list as output. I thought the arrays.stream.boxed would have returned an unmodifiable list and I tried to change as
new ArrayList<>(Arrays.stream....)
But still, I am getting the same output.
Could someone please help with this issue?
First thing, the method subList won't modify the reference on which it is invoked. That means when you call priceList.subList(3, priceList.size()) the priceList isn't getting modified instead, the method returns a new List based on the range. Since you didn't assign it to a variable you cannot access it. So, when you invoke subList method you will have two lists one will be the main list (priceList which won't be modified) and a new subList.
Approach-1
Assign the sub list to a new variable/reference, that way you can use that list in the later portions of the code
List<Integer> subList = priceList.subList(3, priceList.size());
for(Integer price : subList) {
System.out.println(price);
}
Approach-2
If you don't want the sublist in the later portions of your code, supply the return of the subList method to the for-each loop.
for(Integer price : priceList.subList(3, priceList.size())) {
System.out.println(price);
}