[Java] From two Lists to one array list


I verified it because I need to do the title to make a stacked bar graph. At first, I implemented it with a fixed class, but when I tried to use it for general purposes, I stumbled, so don't forget it.




From a list of two Integers to one list of Integer arrays The two lists are assumed to be the same size.

Integer version

private List<Integer[]> convertTwoListToArray1(List<Integer> list1, List<Integer> list2) {
    List<Integer[]> list = new ArrayList<>();
    for (int i = 0; i < list1.size(); i++) {
        list.add(new Integer[] { list1.get(i), list2.get(i) });
    return list;

Click here for the generic version that I tried to generalize

Generics version

private <T> List<T[]> convertTwoListToArray2(List<T> list1, List<T> list2) {
    List<T[]> list = new ArrayList<>();
    for (int i = 0; i < list1.size(); i++) {
        Object[] tmpArray = new Object[] { list1.get(i), list2.get(i) };
        list.add((T[]) tmpArray);
    return list;


I stumbled because I couldn't create an array of generics, but I solved it by casting an array of Objects.

that's all

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