java push to array 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 array add element

// A better solution would be to use an ArrayList which can grow as you need it. 
// The method ArrayList.toArray( T[] a ) 
// gives you back your array if you need it in this form.

List<String> where = new ArrayList<String>();
where.add(element);
where.add(element);

// If you need to convert it to a simple array...

String[] simpleArray = new String[ where.size() ];
where.toArray( simpleArray );

Example 3: 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;