Exceptions

[Chris Judd]

I'm having a hard time understanding why E is considered a correct answer to this question. The book lists NumberFormatException as a Programmatically throw exeption. I thought that means that it is a checked exception...how can I tell what is a checked excption and what is an unchecked exception?

Thanks for your help,
Chris

From 400 Chapter 5: Flow Control, Exceptions, and Assertions of the K & B book:

import java.io.*;
class Master {
String doFileStuff() throws FileNotFoundException { return "a"; }
}
class Slave extends Master {
public static void main(String[] args) {
String s = null;
try { s = new Slave().doFileStuff();
} catch ( Exception x) {
s = "b"; }
System.out.println(s);
}
// insert code here
}

Which, inserted independently at // insert code here, will compile, and produce the output
b? (Choose all that apply.)
A. String doFileStuff() { return "b"; }
B. String doFileStuff() throws IOException { return "b"; }
C. String doFileStuff(int x) throws IOException { return "b"; }
D. String doFileStuff() throws FileNotFoundException { return "b"; }
E. String doFileStuff() throws NumberFormatException { return "b"; }
F. String doFileStuff() throws NumberFormatException,
FileNotFoundException { return "b"; }

[Keith Lynn]

An unchecked exception is either RuntimeException, Error, or one of their subclasses.

In this case, you are not required to list the classes in the throws clause of the overriden method in the throws clause of the overriding method.

Also you are allowed to add unchecked exception to the throws clause of the overridding method.

[Chris Judd]

Thanks Keith!