ex

public class Example {
    public static void main(String[] args) {
        int[] numbers = {1,2,3};
      // copy a new array
int[] newNumbers = new int[numbers.length+1];

for(int i=0; i<numbers.length;i++){
  newNumbers[i] = numbers[i];
}
newNumbers[numbers.length]=4; 
    }
}