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 String
s.
The output of the program is:
element 0: Amy element 1: Bob element 2: Cindy
The 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.)
Suppose that the following follows the first three add
statements:
names.add("Daniel");
Where will the reference to "Daniel" be added?