append value to array java code example

Example 1: how to append to an array in java

import java.util.Arrays;

class ArrayAppend {
    public static void main( String args[] ) {
      int[] arr = { 10, 20, 30 };
      System.out.println(Arrays.toString(arr));

      arr = Arrays.copyOf(arr, arr.length + 1);
      arr[arr.length - 1] = 40; // Assign 40 to the last element
      System.out.println(Arrays.toString(arr));
    }
}

Example 2: java add element to existing array

//original array
String[] rgb = new String[] {"red", "green"};
//new array with one more length
String[] rgb2 = new String[rgb.length + 1];
//copy the old in the new array
System.arraycopy(rgb, 0, rgb2, 0, rgb.length);
//add element to new array
rgb2[rgb.length] = "blue";
//optional: set old array to new array
rgb = rgb2;

Example 3: how to append values in integer array in java

import java.util.ArrayList;
import java.util.Arrays;
import java.util.List;
 
class Main
{
    private static Integer[] append(Integer[] arr, int element) {
        List<Integer> list = new ArrayList<>(Arrays.asList(arr));
        list.add(element);
 
        return list.toArray(new Integer[0]);
    }
 
    public static void main(String[] args) {
 
        Integer[] nums = { 1, 2, 3, 4 };
 
        nums = append(nums, 5);     // add 5 to nums[]
        System.out.println(Arrays.toString(nums));
    }
}

Example 4: how to add a number to an array in java

List<Integer> myList = new ArrayList<Integer>();
myList.add(5);
myList.add(7);