Deck 12: Exceptions and Advanced File Io

Question 1

If the IOData.dat file does not exist,what will happen when the following statement is executed? RandomAccessFile randomFile =
New RandomAccessFile("IOData.dat","rw");

A) A FileNotFoundException will be thrown
B) An IOExcepton will be thrown
C) The file IOData.dat will be created
D) This is a critical error,the program will stop execution

Answer 1

C

Question 2

All exceptions are instances of classes that extend this class.

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

Answer 2

B

Question 3

In a try/catch construct,after the catch statement is executed

A) the program returns to the statement following the statement in which the exception occurred.
B) the program terminates.
C) the program resumes at the statement that immediately follows the try/catch construct.
D) the program resumes at the first statement of the try statement.

Answer 3

C

Question 4

All of the exceptions that you will handle are instances of classes that extend this class.

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

Question 5

A(n)________ is an object that is generated in memory as the result of an error or an unexpected event.

A) exception handler
B) exception
C) default exception handler
D) error message

Question 6

This is a section of code that gracefully responds to exceptions when they are thrown.

A) Thrown class
B) Default exception handler
C) Exception
D) Exception handler

Question 7

Look at the following code: FileInputStream fstream =
New FileInputStream("MyInfo.dat");
DataInputStream inputFile =
New DataInputStream(fstream);
This code can also be written as:

A) FileInputStream inputFile =
New FileInputStream(new DataInputStream("MyInfo.dat"));
B) DataInputStream inputFile =
New DataInputStream(new FileInputStream("MyInfo.dat"));
C) FileInputStream fstream =
New DataInputStream("InputFile.txt");
D) DataInputStream inputFile =
New DataInputStream("InputFile.txt");

Question 8

If the code in a method can potentially throw a checked exception,then that method must

A) handle the exception
B) have a throws clause listed in the method header
C) Neither a or b
D) Either a or b

Question 9

When writing a string to a binary file or reading a string from a binary file,it is recommended that you use

A) Methods that use UTF-8 encoding
B) The Scanner class methods
C) The FileReader and Writer class methods
D) The System.In and System.Out methods

Question 10

To read data from a binary file you create objects from the following classes:

A) FileInputStream and DataInputStream
B) File and PrintWriter
C) File and Scanner
D) BinaryFileReader and BinaryDataReader

Question 11

To write data to a binary file you create objects from the following classes:

A) File and PrintWriter
B) File and Scanner
C) FileOutputStream and DataOutputStream
D) BinaryFileWriter and BinaryDataWriter

Question 12

In the following code,assume that inputFile references a Scanner object that has been successfully used to open a file: double totalIncome = 0.0;
While (inputFile.hasNext())
{
Try
{
TotalIncome += inputFile.nextDouble();
}
Catch(InputMismatchException e)
{
System.out.println("Non-numeric data encountered " +
"in the file.");
InputFile.nextLine();
}
Finally
{
TotalIncome = 35.5;
}
}
What will be the value of totalIncome after the following values are read from the file?
2)5
8)5
3)0
5)5
Abc
1)0

A) 19.5
B) 0.0
C) 35.5
D) 75.0

Question 13

Why does the following code cause a compiler error? try
{
Number = Integer.parseInt(str);
}
Catch (IllegalArgumentException e)
{
System.out.println("Bad number format.");
}
Catch (NumberFormatException e)
{
System.out.println(str + " is not a number.");
}

A) Because you can have only one catch clause in a try statement.
B) Because NumberFormatException inherits from IllegalArgumentException.The code should handle NumberFormatException before IllegalArgumentException.
C) Because the Integer.parseInt method does not throw a NumberFormatException.
D) Because the Integer.parseInt method does not throw an IllegalArgumentException.

Question 14

The following catch statement can catch (Exception e){…}

A) can handle all exceptions that are instances of the Exception class,but not a subclass of Exception.
B) handle all throwable objects by using polymorphic reference as a parameter in the catch clause.
C) handle all exceptions that are instances of the Exception class or a subclass of Exception.
D) is an error since no objects are instantiated in the Exception class.

Question 15

When an exception is thrown,

A) it must always be handled by the method that throws it.
B) the program terminates even if the exception is handled.
C) it must be handled by the program or by the default exception handler.
D) it may be ignored.

Question 16

Given the following constructor code,which of the statements are true? public Book(String ISBNOfBook,double priceOfBook,
Int numberOrderedOfBook)
{
If (ISBNOfBook == "")
Throw new BlankISBN();
If (priceOfBook < 0)
Throw new NegativePrice(priceOfBook);
If (numberedOrderedOfBook < 0)
Throw new NegativeNumberOrdered(numberOrderedv);
ISBN = ISBNOfBook;
Price = priceOfBook;
NumberedOrdered = numberOrderedOfBook;
}

A) There is an error: a throws clause should be added to the constructor header.
B) Classes extending the Exception class should be created for each of the custom exceptions that are thrown in the constructor.
C) The calling method must handle the exceptions thrown in the constructor,or have its own throws clause specifying them.
D) All of the above.

Question 17

An exception's default error message can be retrieved using this method.

A) getMessage()
B) getErrorMessage()
C) getDefaultMessage()
D) getDefaultErrorMessage()

Question 18

The IllegalArgumentException class extends the RuntimeException class,and is therefore

A) a checked exception class.
B) an unchecked exception class
C) never used directly
D) None of the above

Question 19

What will be the result of the following statements? FileInputStream fstream =
New FileInputStream("DataIn.dat");
DataInputStream inFile =
New DataInputStream(fstream);

A) The inFile variable will reference an object that is able to read only text data from the Input.dat file.
B) The inFile variable will reference an object that is able to read binary data from the Input.dat file.
C) The inFile variable will reference an object that is able to write binary data to the Input.dat file.
D) The inFile variable will reference an object that is able to read random access data from the Input.dat file

Question 20

If,within one try statement you want to have catch clauses of the following types,in which order should they appear in your program: (1)Exception
(2)IllegalArgumentException
(3)RuntimeException
(4)Throwable

A) 1,2,3,4
B) 2,3,1,4
C) 4,1,3,2
D) 3,1,2,4

Question 21

In a catch statement,what does the following code do? System.out.println(e.getMessage());

A) It prints the stack trace.
B) It prints the error message for an exception.
C) It prints the code that caused the exception.
D) It overrides the toString method

Question 22

What will be the result of the following code? FileOutputStream fstream new FileOutputStream("Output.dat");
DataOutputStream outputFile = new DataOutputStream(fstream);

A) The outputFile variable will reference an object that is able to write text data only to the Output.dat file.
B) The outputFile variable will reference an object that is able to write binary data to the Output.dat file.
C) The outputFile variable will reference an object that is able to read binary data from the Output.dat file.
D) The outputFile variable will reference an object that is able to write to Output.dat as a random access file.

Question 23

If you want to append data to the existing binary file,BinaryFile.dat,use the following statements to open the file.

A) FileOutputStream fstream =
New FileOutputStream("BinaryFile.dat");
DataOutputStream binaryOutputFile =
New DataOutputStream(fstream);
B) FileOutputStream fstream =
New FileOutputStream("BinaryFile.dat",false);
DataOutputStream binaryOutputFile =
New DataOutputStream(fstream);
C) FileOutputStream fstream =
New FileOutputStream("BinaryFile.dat",true);
DataOutputStream binaryOutputFile =
New DataOutputStream(fstream);
D) FileOutputStream fstream =
New FileOutputStream("BinaryFile.dat");
DataOutputStream binaryOutputFile =
New DataOutputStream(fstream,true);

Question 24

When the code in a try block may throw more than one type of exception,you need to write a catch clause for each type of exception that could potentially be thrown.

Question 25

What will the following code display? String input = "99#7";
Int number;
Try
{
Number = Integer.parseInt(input);
}
Catch(NumberFormatException ex)
{
Number = 0;
}
Catch(RuntimeException ex)
{
Number = 1;
}
Catch(Exception ex)
{
Number = -1;
}
System.out.println(number);

A) 99
B) 997
C) 0
D) 1

Question 26

In order for an object to be serialized,its class must implement this interface.

A) Serial
B) Writable
C) Serializable
D) ObjectOutputStream

Question 27

If a method does not handle a possible checked exception,what must the method have?

A) A catch clause in its header
B) A try/catch clause in its header
C) A try clause in its header
D) A throws clause in its header

Question 28

Unchecked exceptions are those that inherit from

A) the Error class or the RuntimeException class.
B) the Error class or the Exception class.
C) the Exception Class or the RuntimeException class.
D) only the Error class.

Question 29

When you write a method that throws a checked exception,you must

A) have a throws clause in the method header.
B) override the default error method.
C) use each class only once in a method.
D) ensure that the error will occur at least once each time the program is executed.

Question 30

The catch clause

A) follows the try clause.
B) starts with the word catch followed by a parameter list in parentheses containing an ExceptionType parameter variable.
C) contains code to gracefully handle the exception type listed in the parameter list.
D) All of the above.

Question 31

If the program does not handle an unchecked exception,

A) the exception is ignored.
B) the program is halted and the default exception handler handles the exception.
C) the program must handle the exception.
D) this will cause a compilation error.

Question 32

The call stack is an internal list of all the methods that are currently executing.

Question 33

If,within one try statement you want to have catch clauses that catch exceptions of the following types,in which order should they appear in your program? (1)Throwable
(2)Exception
(3)RuntimeException
(4)NumberFormatException

A) 4,3,2,1
B) 2,3,1,4
C) 4,1,3,2
D) 3,1,2,4

Question 34

Assume that the classes BlankISBN,NegativePrice,and NegativeNumberOrdered are exception classes that inherit from Exception.The following code is a constructor for the Book class.What must be true about any method that instantiates the Book class with this constructor? public Book(String ISBNOfBook,double priceOfBook,
Int numberOrderedOfBook)throws BlankISBN,
NegativePrice,
NegativeNumberOrdered
{
If (ISBNOfBook == "")
Throw new BlankISBN();
If (priceOfBook < 0)
Throw new NegativePrice(priceOfBook);
If (numberedOrderedOfBook < 0)
Throw new NegativeNumberOrdered(numberOrderedv);
ISBN = ISBNOfBook;
Price = priceOfBook;
NumberedOrdered = numberOrderedOfBook;
}

A) It must call the constructor with valid data or a compiler error will occur.
B) It must contain an inner class that extends the IOException class.
C) It must handle all of the possible exceptions thrown by the constructor or have its own throws clause specifying them.
D) All of the above.

Question 35

To serialize an object and write it to the file,use this method of the ObjectOutputStream class.

A) SerializeObject
B) WriteObject
C) Serialize
D) SerializeAndWrite

Question 36

The throw statement informs the compiler that a method throws one or more exception.

Question 37

A class must implement the Serializable interface in order for objects of the class to be serialized.

Question 38

If a random access file contains a stream of characters,which of the following would you use to set the pointer on the fifth character?

A) file.seek(4);
B) file.seek(5);
C) file.seek(9);
D) file.seek(8);

Question 39

When an exception is thrown by code in the try block,the JVM begins searching the try statement for a catch clause that can handle it and passes control of the program to

A) each catch clause that can handle the exception.
B) the last catch clause that can handle the exception.
C) the first catch clause that can handle the exception.
D) If there are two or more catch clauses that can handle the exception,the program halts.

Question 40

Classes that inherit from the Error class are

A) for exceptions that are thrown when a critical error occurs,and the application program should not try to handle them.
B) for exceptions that are thrown when a critical error occurs,and the application program should try to handle them.
C) for exceptions that are thrown when an IOException occurs,and the application program should not try to handle them.
D) for exceptions that are thrown when an IOException error occurs,and the application program should try to handle them.

Question 41

When deserializing an object using the readObject method,you must cast the return value to the desired class type.

Question 42

A catch clause that uses a parameter variable of the Exception type is capable of catching any exception that extends the Error class.

Question 43

The throws clause causes an exception to be thrown.

Question 44

When an exception is thrown by a method that is executing under several layers of method calls,a stack trace indicates the method executing when an exception occurred and all of the methods that were called in order go execute that method.

Question 45

If class,SerializedClass,contains references to objects of other classes as fields,those classes must also implement the Serializable interface in order to be serialized.

Question 46

When an object is serialized,it is converted into a series of bytes that contain the object's
data.