Java ArrayList for integers

Question

I have values that I\'d like to add into an ArrayList to keep track of what numbers have shown up. The values are integers so I created an ArrayList;

ArrayLi         


        

Answer 1

you are not creating an arraylist for integers, but you are trying to create an arraylist for arrays of integers.

so if you want your code to work just put.

List<Integer> list = new ArrayList<>();
int x = 5;
list.add(x);

Answer 2

Here there are two different concepts that are merged togather in your question.

First : Add Integer array into List. Code is as follows.

List<Integer[]> list = new ArrayList<>();
Integer[] intArray1 = new Integer[] {2, 4};
Integer[] intArray2 = new Integer[] {2, 5};
Integer[] intArray3 = new Integer[] {3, 3};
Collections.addAll(list, intArray1, intArray2, intArray3);

Second : Add integer value in list.

List<Integer> list = new ArrayList<>();
int x = 5
list.add(x);