Java ArrayList replace at specific index

Question

I need help with this java please. I created an ArrayList of bulbs, and I\'m trying to replace a bulb at specific index with another bulb. So with the following heading, how

Answer 1

public void setItem(List dataEntity, Item item) {
    int itemIndex = dataEntity.indexOf(item);
    if (itemIndex != -1) {
        dataEntity.set(itemIndex, item);
    }
}