How to add an element at the end of an array?

Jeffrey Zong picture Jeffrey Zong · Feb 16, 2015 · Viewed 109.1k times · Source

I want to know how to add or append a new element to the end of an array. Is any simple way to add the element at the end? I know how to use a StringBuffer but I don't know how to use it to add an element in an array. I prefer it without an ArrayList or list. I wonder if the StringBuffer will work on integers.

Answer

Tunaki picture Tunaki · Feb 16, 2015

You can not add an element to an array, since arrays, in Java, are fixed-length. However, you could build a new array from the existing one using Arrays.copyOf(array, size) :

public static void main(String[] args) {
    int[] array = new int[] {1, 2, 3};
    System.out.println(Arrays.toString(array));
    array = Arrays.copyOf(array, array.length + 1); //create new array from old array and allocate one more element
    array[array.length - 1] = 4;
    System.out.println(Arrays.toString(array));
}

I would still recommend to drop working with an array and use a List.