Example Program

Here is an example program. methodA has two try/catch structures. The first uses the static method parseInt() of class Integer to convert a string of characters into a primitive int.

If the string can't be converted, parseInt() throws a NumberFormatException.

The second try/catch structure calls methodB, which might throw an ArithmeticException. If that happens, the second catch{} will handle it.

The clause throws ArithmeticException in the header of methodB() is not required, because ArithmeticExceptions are not checked.

import java.lang.* ;
import java.io.* ;

public class BuckPasser
{
  public static int methodB( int divisor )  throws ArithmeticException
  {
    int result = 12 / divisor;  // may throw an ArithmeticException
    return result;
  }

  public static void methodA( String input )
  {
    int value = 0;

    try
    {
      value = Integer.parseInt( input );     // Convert the string to an int.
                                             // May throw a NumberFormatException    
    }
    catch ( NumberFormatException badData )
    {
      System.out.println( "Bad Input Data!!" );
      return;   // this is necessary; without it control will continue with the next try.
    }

    try
    {
      System.out.println( "Result is: " + methodB( value ) );
    }
    catch ( ArithmeticException zeroDiv )
    {
      System.out.println( "Division by zero!!" );
    }

  }

  public static void main ( String[] a ) 
  { 
    Scanner scan = new Scanner( System.in );
    String  inData;
    
    System.out.print("Enter the divisor: ");
    inData = scan.next();  // Read a string from standard input
    methodA( inData );     // send the string to methodA
  }
}

Here is what happens when the user enters 0 for a divisor:

main() calls MethodA
MethodA calls MethodB
MethodB causes an ArithmeticException by dividing by zero
MethodB throws the exception back to MethodA
MethodA catches the exception and prints "Division by zero!!"
Control returns to main(), which exits normally.

Answer:

Example Program

QUESTION 9: