Exception Handling - Beginning Java 8 Fundamentals - page 340

The following snippet of code uses a valid sequence of multiple catch blocks. The ArithmeticException class
is a subclass of the RuntimeException class. If both of these exceptions are handled in catch blocks for the same try
block, the most specific type, which is ArithmeticException , must appear before the most generic type, which is
RuntimeException .
try {
// Do something, which might throw Exception
}
catch(ArithmeticException e1) {
// Handle ArithmeticException first
}
catch(RuntimeException e2) {
// Handle RuntimeException after ArithmeticException
}
Checked and Unchecked Exceptions
Before I start discussing checked and unchecked exceptions, let's look at a Java program that reads a character from
the standard input. You have been using the System.out.println() method to print messages on the standard
output, which is typically the console. You can use the System.in.read() method to read a byte from the standard
input, which is typically the keyboard. It returns the value of the byte as an int between 0 and 255. It returns -1 if
the end of input is reached. The following is the code that reads a byte from the standard input and returns it as a
character. It assumes that the language you are using has all alphabets whose Unicode values are between 0 and 255.
The readChar() method has the main code. To read a character from the standard input, you will need to use the
ReadInput.readChar() method.
// ReadInput.java
package com.jdojo.exception;
public class ReadInput {
public static char readChar() {
char c = '\u0000';
int input = System.in.read();
if (input != -1) {
c = (char)input;
}
return c;
}
}
Try to compile the ReadInput class. Oops! The compiler could not compile ReadInput class. It generated the
following error message:
"ReadInput.java": unreported exception java.io.IOException; must be caught or declared to be thrown
at line 7, column 31
The compiler error is pointing to line 7 in the source code:
int input = System.in.read();