6. Example Program Continued

Answer:
The list will hold references to Integer objects.

import java.util.* ;

public class ArrayListEg
{

  public static void main ( String[] args)
  {
    // Create an ArrayList that holds references to String
    ArrayList<String> names = new ArrayList<String>();

    // Add three String references
    names.add("Amy");
    names.add("Bob");
    names.add("Cindy");
       
    // Access and print out the three String Objects
    System.out.println("element 0: " + names.get(0) );
    System.out.println("element 1: " + names.get(1) );
    System.out.println("element 2: " + names.get(2) );
  }
}              

In the program, the ArrayList holds references of type String or a subclass of String.

In the picture, three elements have been added. The references are added in order starting with cell 0 of the array.

Then the program accesses the references using the get() method and prints out the Strings. The output of the program is:

element 0: Amy
element 1: Bob
element 2: Cindy

The names.get( int index ) method returns the reference in the cell at index. If the cell is empty, an IndexOutOfBoundsException will be thrown and the program will halt (unless there is code to handle the exception.)

Question 6:
Suppose that the following follows the first three add statements:
    names.add("Daniel"); 
Where will the reference to "Daniel" be added?