When working with any collection, sometimes you will want to obtain an actual array that contains the contents of the list. You can make use of toArray() method from Collection interface.

 import java.util.ArrayList;

public class ArrayListToArray {

  public static void main(String[] args) {

    //create an array list
    ArrayList al = new ArrayList();

    //Add elements to the array list
    al.add(new Integer(1));
    al.add(new Integer(2));
    al.add(new Integer(3));
    al.add(new Integer(4));
    al.add(new Integer(5));

    System.out.println("contents of al : "+ al );
    Object ia[] = al.toArray();   //get array
    int sum = 0;
    
    //sum the array 
    for(int i=0;i<ia.length;i++)
      sum+=((Integer)ia[i]).intValue();

    System.out.println("Sum is :" + sum);
    
  }

}

Output Screen:

contents of al : [1, 2, 3, 4, 5]
Sum is :15