boon/src/main/java/org/boon/collections/IntList.java
@Override
    public Integer set(int index, Integer element) {
        int oldValue = values[index];
        values[index] = element;
        return oldValue;
    }
@Override
    public Integer set(int index, Integer element) {
        int oldValue = values[index];
        values[index] = element;
        return oldValue;
    }
Set a value in the list.

@param index   index
@param element new value
@return old value at this index