ArrayLists and Iterators

Read this chapter about lists and the useful methods that are available for adding and inserting elements into a list. 

4. ArrayList class



Answer:
An ArrayIndexOutOfBounds exception is thrown and (usually) the program halts.









    

        
ArrayListObject
ArrayList class
The ArrayList class builds
            upon the capabilities of arrays. An ArrayList object contains an array of object references plus many methods for managing that array.

        
The biggest convenience of a ArrayList is that you can keep adding elements to it no matter what size it was originally. The size of the ArrayList automatically increases and no information
            will be lost.

        
However, this convenience comes at a price:

        
    
            
  1. The elements of an ArrayList must be object references, not primitive data like int or double.
    2. 
            
  2. ArrayList operations are slightly slower than array operations.
    3. 
        

        
In the picture, "X" shows that a cell is empty. The ArrayList in the picture is completely empty. The "X" is conceptual; the actual implementation of ArrayList uses an unspecified means to keep track
            of empty cells.

        
Note: "X" is not the value null. If null is placed in a cell, the cell is regarded as containing data.

        

            

        

        

    

    

        

    



    
Question 4:
(Thought Question: ) Say that you want a list of int values. But an ArrayList can contain only object references. How can you use an ArrayList to store your ints? (Click for a hint.)