Here's what we had before... TerminalClient.java

Scanner class has overloaded constructors.
Which one does TerminalClient.java use?
( of these... )

FileIOClient.java

ok, we have a CHECKED exception
which means it WON't COMPILE... (see error message)

[ldale@bianca fileIO]$ javac FileIOClient.java 
FileIOClient.java:24: unreported exception java.io.FileNotFoundException; must be caught or declared to be thrown
      Scanner sc = new Scanner(new File(fileName));
                   ^
1 error

In contrast to unchecked exceptions
• NullPointerException
  Which occurs when?
• ArrayIndexOutOfBoundsException
  Which occurs when?
• NumberFormatException
  Which occurs when?
• InputMismatchException
  Which occurs when?
• IllegalFormatConversionException
  Which occurs when?
• Others......
All of which compile to be caught at runtime
when they propagate to the operating system KA-BOOM!!!

FileIOClient_2a.java     &     FileIOClient_2b.java

Our original error message reminds us of our choices with checked exceptions.

1. declared to be thrown

   
   [ldale@bianca fileIO]$ diff FileIOClient.java FileIOClient_2a.java 
   4c4
   < public class FileIOClient{
   ---
   > public class FileIOClient_2a{
   6c6
   <   public static void main(String [] args){
   ---
   >   public static void main(String [] args) throws FileNotFoundException {
   
   

2. caught

   
   [ldale@bianca fileIO]$ diff FileIOClient.java FileIOClient_2b.java 
   4c4
   < public class FileIOClient{
   ---
   > public class FileIOClient_2b{
   22a23,24
   >     try {
   > 
   38a41,46
   >     } catch (FileNotFoundException e) {
   >       System.out.printf("\n\n\tERROR: Your file %s is not found."
   >                         +          "  Please locate and try again.\n\n"
   >                         , fileName );
   >     }
   >