Deck 12: Exception Handling

Question 1

When a program contains multiple ____ blocks, they are examined in sequence until a match is found for the type of exception that occurred.

A) throw
B) finally
C) catch
D) try

Answer 1

C

Question 2

A catch block is a method that can be called directly and takes an argument that is some type of exception.

Answer 2

False

Question 3

Placing data conversion attempts in a try block allows you to handle potential data conversion errors caused by careless user entry.

Answer 3

True

Question 4

To create your own throwable Exception class, you must extend a subclass of Catchable .

Question 5

Since variables declared within a try or catch block are local to that block, the variable goes out of scope when the try or catch block ends.

Question 6

The keyword catch followed by an Exception type in the method header is used when a method throws an exception that it will not catch but that will be caught by a different method.

Question 7

To use a method to its full potential, you must know the method name, return type, type and number of arguments required, and type and number of exceptions the method throws.

Question 8

____ represents the degree to which a system is resilient to stress, maintaining correct functioning.

A) Endurance
B) Robustness
C) Fault-tolerant
D) Strength

Question 9

Although a method can throw any number of ____ types, many developers believe that it is poor style for a method to throw and catch more than three or four types.

A) Error
B) Clause
C) Exception
D) Catch

Question 10

Some programmers refer to a catch block as a catch ____.

A) method
B) phrase
C) statement
D) clause

Question 11

A(n) ____ statement is one that sends an Exception object to a catch block.

A) throw
B) catch
C) optional
D) assert

Question 12

A variable declared within a try or catch block is ____ to that block.

A) local
B) universal
C) public
D) unique

Question 13

When you have actions you must perform at the end of a try…catch sequence, you can use a ____ block.

A) finally
B) catch
C) throw
D) try

Question 14

You can place as many statements as you need within a try block, and you can catch as many exceptions as you want.

Question 15

The parent class of Error is ____.

A) Object
B) Exception
C) RuntimeError
D) RuntimeException

Question 16

Unplanned exceptions that occur during a program's execution are also called execution exceptions.

Question 17

The ____ class represents more serious errors from which your program usually cannot recover.

A) Error
B) Throwable
C) Exception
D) Menu

Question 18

____ statements are program statements that can never execute under any circumstances.

A) Stagnant
B) Error
C) Unreachable
D) Exception

Question 19

The code within a finally block cannot execute if the preceding try block identifies an exception.

Question 20

When an exception is a checked exception, client programmers are forced to deal with the possibility that an exception will be thrown.

Question 21

Which method constructor constructs a new exception with the specified detail message and cause?

A) Exception()
B) Exception(String message)
C) Exception(String message, Throwable cause)
D) Exception(Throwable cause)

Question 22

The ____ option must be used when running a program in order to see the results of assert statements.

A) -db
B) -ea
C) -debug
D) -assert

Question 23

The Java compiler does not require that you catch or specify ____ exceptions.

A) checked
B) runtime
C) return
D) optional

Question 24

In order to use a variable both with a try or catch block and afterward, you must declare the variable before the ____ block begins.

A) catch
B) try
C) main
D) finally

Question 25

In the case where a method might throw more than one exception type, you specify a list of potential exceptions in the method header by separating them with ____.

A) spaces
B) semicolons
C) commas
D) periods

Question 26

If you create an object using Java's  BigDecimal  class, and then perform a division that results in a non-terminating decimal division such as 1/3, but specify that an exact result is needed, a(n) ____ is thrown.

A) DivisionByZero
B) ArithmeticException
C) InternalError
D) MismatchException

Question 27

Programs would be less clear if you had to account for ____ exceptions in every method declaration.

A) unthrown
B) thrown
C) runtime
D) checked

Question 28

____ exceptions are the type that programmers should anticipate and from which programs should be able to recover.

A) Unchecked
B) Runtime
C) Checked
D) Thrown

Question 29

Any ____ block might throw an  Exception  for which you did not provide a  catch  block.

A) try
B) throws
C) finally
D) Exception

Question 30

The ____ class comprises less serious errors that represent unusual conditions that arise while a program is running and from which the program can recover.

A) IOException
B) Error
C) OutOfMemoryError
D) Exception

Question 31

If a method throws an exception that it will not catch but that will be caught by a different method, you must also use the keyword ____ followed by an Exception type in the method header.

A) finally
B) try
C) catch
D) throws

Question 32

What is the correct syntax of an assert statement?

A) assert AssertionError : optionalErrorMessage
B) assert booleanExpression : optionalErrorMessage
C) assert stringExpression : optionalErrorMessage
D) assert booleanExpression = optionalErrorMessage

Question 33

A(n) ____ is a Java language feature that can help you detect logic errors that do not cause a program to terminate, but nevertheless produce incorrect results.

A) error checker
B) thread
C) assertion
D) throw statement

Question 34

When you catch an  Exception  object, you can call ____ to display a list of methods in the call stack so you can determine the location of the statement that caused the exception.

A) callStackTrace()
B) printStackTrace()
C) whereIs()
D) printStack()

Question 35

Which of the following is NOT a component of a try block?

A) a closing curly brace
B) the keyword try
C) executable statements
D) a throw statement

Question 36

Assertions are meant to be helpful in the ____ stage of a program.

A) development
B) testing
C) production
D) modeling

Question 37

The memory location known as the ____ is where the computer stores the list of method locations to which the system must return.

A) local store
B) RAM
C) call stack
D) fixed partition

Question 38

If you want to ensure that a user enters numeric data, you should use ____ techniques that provide the means for your program to recover from the mistake.

A) error-handling
B) looping
C) exception-handling
D) decision

Question 39

When you use a(n) ____ statement, you state a condition that should be true , and Java throws an AssertionError when it is not.

A) if
B) boolean
C) assert
D) exception

Question 40

A(n) ____ clause is used in the method header so that applications that use your methods are notified of the potential for an exception.

A) throws
B) return
C) stack
D) exception

Question 44

How is an Error class different from an Exception class?

Question 54

What is an Exception class? Give an example.

Question 55

What things might a programmer do to cause a potential exception in a program?

Question 58

What are the elements that make up a try block?

Question 60

When a program contains multiple catch blocks, how are they handled?

Question 61

public static void main(String args[])
{
   int a, b;
   try
   {
      a = 0;
      b = 42 / a;
      System.out.println("This will not be printed.");
   }  
​
   catch (ArithmeticException e)
   {
      System.out.println("Division by zero.");
   }
   System.out.println("After catch statement.");
}
The program above includes a try block and a catch clause that processes the ArithmeticException generated by the division-by-zero error. Explain how the try and catch blocks operate, and what the output will be following program execution.

Question 62

In the above code, explain the importance of the shaded statement. What occurs if the statement is commented out of the program?

Question 63

Using the example code above, complete the statement of the catch block to generate the message that comes with the caught ArithmeticException .

Question 64

What is a finally block and how would a programmer use it?

Question 65

import java.util.*;
import java.util.Scanner;
public class AssertionExample
{
    public static void main( String args[] )
   {
       Scanner scanner = new Scanner( System.in );
       System.out.print( "Enter a number between 0 and 20: " );
       int value = scanner.nextInt();
       ---Code here---
       "Invalid number: " + value;
       System.out.printf( "You have entered %d\n", value );
   }
}
In the code above, when the user enters the number, the scanner.nextInt() method reads the number from the command line. In the blank line provided, create an assert statement that determines whether the entered  number is within the valid range (between 0 and 20). If the user entered a number that is out of range, then the "Invalid number" error should occur.

Question 66

What are unchecked exceptions? Give an example.

Question 67

import java.util.*;
public class DivisionMistakeCaught3
{
    public static void main(String[] args)
    {
       Scanner input = new Scanner(System.in);
       int numerator, denominator, result;
       try
       {
          System.out.print("Enter numerator >> ");
          numerator = input.nextInt();
          System.out.print("Enter denominator >> ");
          denominator = input.nextInt();
          result = numerator / denominator;
          System.out.println(numerator + " / " + denominator + " = " + result);
       }
       catch(ArithmeticException mistake)
       {
          System.out.println(mistake.getMessage());
       }
       catch(InputMismatchException mistake)
       {
          System.out.println("Wrong data type");
       }  
    }
}
Using the above code, describe what will happen if a user enters two usable integers. What will happen if a user enters an invalid noninteger value? What will happen if the user enters 0 for the denominator?

Question 68

An alternative to hard coding error messages into your Exception classes is creating a catalog of possible messages to use. What are the advantages of doing so?

Question 69

The example code above uses the getMessage() method. Explain how the getMessage() method makes error message generation more specific to the error encountered.

Question 70

public class exceptions
{
    public static void main(String Args[])
    {
       int[] array = new int[3];
       try
       {
          for(int a=0;a<4;++a)
          {
             array[a] = a;
          }
          System.out.println(array);
       }
       catch(ArrayIndexOutOfBoundsException e)
       {
          System.out.println("Out of bounds");
       }
    }
}
In the above code, the line System.out.println(array); gets skipped when an exception occurs. Write a finally block that will execute, and will execute a System.out.println(array); if there is an exception.

Question 71

The figures above show the HighBalanceException and CustomerAccount classes. Explain what is involved in creating your own throwable Exception s. Explain what will happen if the CustomerAccount throws a HighBalanceException .

Question 72

What advantages does object-oriented exception handling provide?

Question 73

What is unreachable code and how might using multiple catch blocks cause this? Provide an example.

Question 74

The example code above depicts a try block and a catch block. Describe how the try and catch blocks operate when illegal integer division is attempted. Describe what will happen if valid values are entered.

Question 75

The figure above shows a call stack. Explain how a call stack works.

Question 76

import java.util.Scanner;
public class AssertTest
  {
        public static void main( String args[] )
        {
            Scanner input = new Scanner( System.in );
​
            System.out.print( "Enter a number between 0 and 10: " );
            int number = input.nextInt();
​
            assert ( number >= 0 && number <= 10 ) : "Invalid number: " + number;
​
           System.out.printf( "You entered %d\n", number );
       }
  }
The above code demonstrates the functionality of the assert statement. Explain what happens when an entered number is valid and when an entered number is out of range.

Question 77

In the example above, the user might not enter an integer, the conversion to an integer might fail, and an exception might be thrown. Why is this a problem and what are some possible options for fixing these types of errors?

Question 78

The figure above represents code that executes in the try block any statements that might throw exceptions, along with a catch and finally block. Explain three different outcomes of the try block that would cause the code in the finally block to execute.

Question 79

What advantage to programmers does the technique of cycling through the methods in the stack offer? Why?