The list will hold references to Integer objects.
The names object of the example program can hold references
to Strings.
The picture shows the ArrayList after three elements
have been added.
The references are added in order starting will cell 0 of the array.
import java.util.* ; class ArrayListEg { public static void main ( String[] args) { // Create an ArrayList that holds references to Object ArrayList<Object> names = new ArrayList<Object>(); // Add three Object references names.add("Amy"); names.add("Bob"); names.add("Cindy"); // Access and print out the three 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) ); } }
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 argument to the get() method acts like an index into an array.
Assume that the following is added after the last statement of the program:
names.add("Daniel");
Where will the reference to "Daniel" be added?