Changing Array Size : Array Basics « Collections « Java Tutorial

Once an array is created, its size cannot be changed. If you want to change the size, you must create a new array and populates it using the values of the old array.

public class MainClass {

  public static void main(String[] args) {
    int[] numbers = { 1, 2, 3 };

    int[] temp = new int[4];
    int length = numbers.length;
    for (int j = 0; j < length; j++) {
      temp[j] = numbers[j];
    numbers = temp;



9.3.Array Basics
9.3.1.How to define an Array
9.3.2.Initializing array elements by index
9.3.3.Alternative Array Declaration Syntax
9.3.4.Anonymous arrays are declared similarly to regular arrays
9.3.5.An array is a Java object
9.3.6.To reference the components of an array
9.3.7.The Length of an Array
9.3.8.Initializing Arrays
9.3.9.Using a for loop to iterate over all the elements and set the values
9.3.10.Arrays of Characters
9.3.11.Using the Collection-Based for Loop with an Array
9.3.12.Changing Array Size
9.3.13.Array Reallocation
9.3.14.Use System.arraycopy to duplicate array
9.3.15.Minimum and maximum number in array
9.3.16.Shuffle elements of an array
9.3.17.Merge (or add) two arrays into one
9.3.18.Circular Buffer