Deck 13: File Input and Output

Question 1

Some text files are ____ files that contain facts and figures, such as a payroll file that contains employee numbers, names, and salaries.

A) application
B) volatile
C) data
D) program

Answer 1

C

Question 2

Java lets you assign a file to a(n) ____ object so that screen output and file output work in exactly the same manner.

A) Stream
B) Input
C) Output
D) File

Answer 2

A

Question 3

FileSystems is a class that contains ____ methods, which assist in object creation.

A) factory
B) file
C) abstract
D) system

Answer 3

A

Question 4

You can use Java's ____ class to create objects that contain information about files or directories, such as their locations, sizes, creation dates, and whether they even exist.

A) Directory
B) Property
C) Path
D) File

Question 5

A ____ is a group of characters that has some meaning.

A) record
B) file
C) byte
D) field

Question 6

Comma-separated values (CSV) is a file format strictly used for working with Java and databases.

Question 7

When you use the BufferedReader class, you must import the java.io package into your program.

Question 8

A data file can be used as a(n) ____ file when each record is accessed one after another in the order in which it was stored.

A) application
B) sequential access
C) stream
D) field

Question 9

You can direct System.err to a new location, such as a disk file or printer, but you cannot direct System.out to a new location.

Question 10

After you create a FileSystem object, you can define a Path using the ____ method with it.

A) getPath()
B) createPath()
C) setPath()
D) getDefault()

Question 11

____ is an abstract class for reading character streams.

A) System.out
B) Reader
C) System.err
D) OutStream

Question 12

Java's Path class is used to create objects that contain information about files and directories, while the Files class performs operations on files and directories.

Question 13

The top-level element in a Path 's directory structure is located at index 1.

Question 14

In random access files, records can be retrieved in any order.

Question 15

If you simply want to display records in order based on their key field, you need to create a random access file.

Question 16

You can store data in variables within a program, but this type of storage is temporary.

Question 17

Permanent storage is usually called computer memory or random access memory (RAM).

Question 18

InputStream is a child of FileInputStream .

Question 19

InputStream and OutputStream are subclasses of the ____ class.

A) IO
B) Object
C) Stream
D) IOStream

Question 20

Placing a file in the ____ directory of your storage device is equivalent to tossing a loose document into a drawer.

A) root
B) path
C) back
D) loose

Question 21

Random files are also called ____________________ files.

Question 22

Because the backslash character starts the escape sequence in Java, you must use two ____ in a string that describes a Path in the DOS operating system.

A) dashes
B) quotes
C) backslashes
D) periods

Question 23

The true benefit of using a(n) ____ file is the ability to retrieve a specific record from a file directly, without reading through other records to locate the desired one.

A) random access
B) text
C) open
D) input

Question 24

The BufferedWriter class contains a ____ method that uses the current platform's line separator.

A) lineSeparator()
B) systemSeparator()
C) newLine()
D) newSeparator()

Question 25

You can use Java's ____ class to create your own random access files.

A) Path
B) FileStream
C) File
D) FileChannel

Question 26

A(n) ____________________ is a collection of fields that contain data about an entity.

Question 27

A(n) ____________________ object is an avenue for reading and writing a file.

Question 28

The String class ____ method accepts an argument that identifies the field delimiter and returns an array of String s.

A) tokens()
B) divide()
C) tokenize()
D) split()

Question 29

____ applications require that a record be accessed immediately while a client is waiting.

A) Sequential
B) Dependent
C) Real-time
D) Batch

Question 30

A(n) ____ field is the field in a record that makes the record unique from all others.

A) unique
B) key
C) search
D) individual

Question 31

____________________ is an abstract class that contains methods for performing output.

Question 32

A file channel is ____, meaning you can search for a specific file location and operations can start at any specified position.

A) moveable
B) seekable
C) flexible
D) dynamic

Question 33

When you use the BufferedReader class, you must import the ____ package into your program.

A) java.nio.file
B) java.io
C) java.nio
D) java.io.input

Question 34

A(n) ____ is a holding place for bytes that are waiting to be read or written.

A) ByteChannel
B) FileChannel
C) InputStream
D) ByteBuffer

Question 35

An array of bytes can be wrapped, or encompassed, into a ByteBuffer using the ByteBuffer ____ method.

A) wrap()
B) convert()
C) export()
D) toArray()

Question 36

The ____ method returns the last Path element in a list of pathnames.

A) toString()
B) getNameCount()
C) getFileName()
D) getName(int)

Question 37

Which of the following statements will write a line separator?

A) newline();
B) BufferedWriter.newline();
C) FileChannel.newline();
D) ByteBuffer.newline();

Question 38

Any of the file input or output methods in a Java program might throw an exception, so all the relevant code in the class is placed in a ____ block.

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

Question 39

The value you store in memory is lost when the program ends or the computer loses power. This type of storage device is called ____________________.

Question 40

You can create a writeable file by using the Files class ____ method.

A) getOutputStream()
B) newOutputStream()
C) newFileOutputStream()
D) fileOutputStream()

Question 41

Describe and provide an example of the differences between real-time applications and interactive programs.

Question 43

import java.nio.file.*;
import java.nio.file.attribute.*;
import java.io.IOException;
public class PathDemo5
{
  public static void main(String[] args)
  {
      Path myPath = Paths.get("C:\\Java\\Input.Output\\MyData.txt");
      try
      {
         ---------Code here ----------
         System.out.println("Creation time " + attr.creationTime());
         System.out.println("Last modified time " + attr.lastModifiedTime());
         System.out.println("Size " + attr.size());
      }
      catch(IOException e)
      {
         System.out.println("IO Exception");
      }
  }
}
Using the above code, create a statement on the indicated line that uses the readAttributes() method of the Files class that takes two arguments-the Path object created in the code and a BasicFileAttributes.class -and returns an instance of the BasicFileAttributes class named attr .

Question 44

while(nextLine = reader.readLine() != null)
    System.out.println(nextLine);
The above loop could be used to read multiple lines from a file. Explain how this loop will execute.

Question 45

What tasks are typically performed when working with stored files in an application?

Question 46

When you perform input and output operations in an application, what is actually occurring with the bytes of information?

Question 47

import java.util.Scanner;
import java.nio.file.*;
public class PathDemo2
{
    public static void main(String[] args)
    {
       String name;
       Scanner keyboard = new Scanner(System.in);
       System.out.print("Enter a file name >> ");
       name = keyboard.nextLine();
       Path inputPath = Paths.get(name);
       ------- Code here -----
       System.out.println("Full path is " + fullPath.toString());
    }
} Using the above code, add a statement on the indicated line that creates an absolute path by assigning the file to the current directory.

Question 48

What is the difference between volatile and nonvolatile storage in Java programming? Give examples of different storage situations.

Question 49

Briefly describe the Path class in Java.

Question 50

writer.write(names, 0, names.length());
The above code represents a write() method of the BufferedWriter class. Describe the purpose of the method and how it accepts the String characters.

Question 51

import java.nio.file.*;
import java.io.*;
import java.nio.channels.FileChannel;
import java.nio.ByteBuffer;
import static java.nio.file.StandardOpenOption.*;
import java.util.Scanner;
public class CreateEmployeesRandomFile
{
   public static void main(String[] args)
   {
     Scanner input = new Scanner(System.in);
     Path file =
       Paths.get("C:\\Java\\Chapter.13\\RandomEmployees.txt");
     String s = "000, ,00.00" +
     System.getProperty("line.separator");
     final int RECSIZE = s.length();
     FileChannel fc = null;
     String delimiter = ",";
     String idString;
     int id;
     String name;
     String payRate;
     final String QUIT = "999";
     try
     {
        fc = (FileChannel)Files.newByteChannel(file, READ, WRITE);
        System.out.print("Enter employee ID number >> ");
        idString = input.nextLine();
       while(!(idString.equals(QUIT)))
       {
         ----Code here-----
         System.out.print("Enter name for employee #" +
              id + " >> ");
         name = input.nextLine();
         System.out.print("Enter pay rate >> ");
         payRate = input.nextLine();
         s = idString + delimiter + name + delimiter +
           payRate + System.getProperty("line.separator");
         byte[] data = s.getBytes();
         ByteBuffer buffer = ByteBuffer.wrap(data);
         ----Code here-----
         fc.write(buffer);
         System.out.print("Enter next ID number or " +
           QUIT + " to quit >> ");
         idString = input.nextLine();
      }
      fc.close();
     }
     catch (Exception e)
    {
       System.out.println("Error message: " + e);
    }
The above program will accept any number of employee records as user input and write the records to a file in a loop. In the first indicated line, create the statement to accept the employee data value from the keyboard as a String and convert it to an integer using the parseInt() method. In the second indicated line, create the statement to compute the record's desired position by multiplying the ID number value by the record size.

Question 52

Explain the difference between an absolute path and a relative path. Provide an example of an absolute path to a file on a system, and then provide an example of a relative path.

Question 53

How can you categorize files by the way they store data?

Question 54

Briefly describe the ByteBuffer class.

Question 55

How can you assign program output to a file, rather than to the standard output device? Explain how this works. Give an example.

Question 56

FileChannel fc = null;
Path file =
Paths.get("C:\\Java\\Chapter.13\\RandomEmployees.txt");
Given the two declarations above, write a Java statement that creates a ByteChannel that is cast to a FileChannel . The file shoould be open for read and write operations.

Question 57

Provide an example of batch processing.

Question 58

When a String is written, placing each record on a new line makes the output file easier to read and interpret. Since not all platforms use '\n' to separate lines, the BufferedWriter class has two alternatives: the newLine() method and the System.getProperty() method. Describe these two methods and how they operate.

Question 59

How can you write the system's newline character to a file in Java?

Question 60

import java.nio.file.*;
import java.io.*;
import java.nio.channels.FileChannel;
import java.nio.ByteBuffer;
import static java.nio.file.StandardOpenOption.*;
public class CreateOneRandomAccessRecord
{
    public static void main(String[] args)
    {
       Path file =
         Paths.get("C:\\Java\\Chapter.13\\RandomEmployees.txt");
       String s = "002,Newmann,12.25" +
         System.getProperty("line.separator");
       --------- Code here -------------
       byte[] data = s.getBytes();
       ByteBuffer buffer = ByteBuffer.wrap(data);
       FileChannel fc = null;
       try
       {
          fc = (FileChannel)Files.newByteChannel(file, READ, WRITE);
          fc.position(2 * RECSIZE);
          fc.write(buffer);
          fc.close();
       }
       catch (Exception e)
      {
          System.out.println("Error message: " + e);
      }
   }
}
The above program creates a single employee record for employee number 002 with a last name of Newmann and a pay rate of 12.25. In the indicated space, create a statement that assigns the length of the string to RECSIZE .

Question 61

import java.nio.file.*;
import java.io.*;
public class ReadEmployeeFile2
{
   public static void main(String[] args)
   {
      Path file =
        Paths.get("C:\\Java\\Chapter.13\\Employees.txt");
     String[] array = new String[3];
     String s = "";
     String delimiter = ",";
     int id;
     String name;
     double payRate;
     double gross;
     final double HRS_IN_WEEK = 40;
     double total = 0;
     try
     {
        InputStream input = new
            BufferedInputStream(Files.newInputStream(file));
        BufferedReader reader = new
           BufferedReader(new InputStreamReader(input));
        System.out.println();
        s = reader.readLine();
        while(s != null)
        {
           -----Code here-----
           id = Integer.parseInt(array[0]);
           name = array[1];
           payRate = Double.parseDouble(array[2]);
           gross = payRate * HRS_IN_WEEK;
           System.out.println("ID#" + id + " " + name +
             " $" + payRate + " $" + gross);
           total += gross;
           s = reader.readLine();
       }
       reader.close();
   }
   catch(Exception e)
   {
       System.out.println("Message: " + e);
    }
   System.out.println(" Total gross payroll is $" + total);
   }
}
The above code demonstrates a retrieved file where Strings are split into usable fields. On the indicated line, write a String class split() method to split the String s that accepts an argument that identifies the field delimiter (in this example, a comma) and returns an array of Strings . The result should be assigned to the String[] array .

Question 62

import java.nio.file.*;
import java.io.*;
import static java.nio.file.StandardOpenOption.*;
public class WriteFile
{
   public static void main(String[] args)
   {
      Path myFile = Paths.get("C:\\Java\\Input.Output\\myNumbers.txt");
      String nums = "12345";
      byte[] data = nums.getBytes();
      OutputStream output = null;
      try
     {
       -----Code here------
       output.write(data)
       output.flush();
       output.close();
     }
     catch(Exception badNums)
     {
         System.out.println("My numbers: " + badNums);
     }
  }
}
Using the above code, add a statement on the indicated line that will create a writeable file by constructing a BufferedOutputStream object and assigning it to the OutputStream . No output should appear on the monitor, but a file should be created.

Question 63

import java.nio.file.*;
import static java.nio.file.AccessMode.*;
import java.io.IOException;
public class PathDemo3
{
  public static void main(String[] args)
  {
    Path myFile = Paths.get("C:\\Java\\Chapter.13\\Data.txt");
    System.out.println("Path is " + myFile.toString());
    try     {
      -------------- Code here -------------------
      System.out.println("File can be read and executed");     }
    catch(IOException e)
    {
       System.out.println("File cannot be used for this application");
    }
   }
}
Assuming you have declared a path named myFile , create the checkAccess() method on the indicated line that will verify that the file exists, and checks that the program can read and write to the file.

Question 64

import java.nio.file.*;
import java.io.*;
public class ReadEmployeeFile
{
   public static void main(String[] args)
   {
      Path file =
        Paths.get("C:\\Java\\Chapter.13\\Employees.txt");
      String s = "";
      try
      {
         InputStream input = new
           BufferedInputStream(Files.newInputStream(file));
         BufferedReader reader = new
           BufferedReader(new InputStreamReader(input));
         -----Code here-----
         while(s != null)
         {
             System.out.println(s);
             -----Code here-----
         }
         reader.close();
     }
     catch(Exception e)
     {
        System.out.println("Message: " + e);
     }
   }
} The above code represents a program that reads an Employees text file. An InputStream is declared for the file, and a BufferedReader is created using the InputStream . On the indicated lines, write a statement that will read the first line into the String . Likewise, in the while statement, write the statement to display the String and read a new line as long as the readLine() method does not return a null value.

Question 65

import java.nio.file.*;
public class PathDemo
{
    public static void main(String[] args)
    {
        Path filePath = Paths.get("C:\\Java\\Input.Output\\LessonInfo.txt");
        int count = filePath.getNameCount();
        System.out.println("Path is " + filePath.toString());
        System.out.println("File name is " +
          filePath.getFileName());
        System.out.println("There are " + count +
          " elements in the file path");
        for(int x = 0; x
            System.out.println("Element " + x + " is " +
            filePath.getName(x));
    }
}
The above code demonstrates the creation of a Path and its method. Describe the output that will display when the code is executed.

Question 66

import java.nio.file.*;
import java.io.*;
public class ReadFile
{
    public static void main(String[] args)
   {
       Path file = Paths.get("C:\\Java\\Input.Output\\Grades.txt");
       InputStream input = null;
       try
      {
          ----Code here-------
          ----Code here-------
           String grade = null;
           grade = reader.readLine();
           System.out.println(grade);
           input.close();
       }
       catch (IOException e)
      {
          System.out.println(e);
       }
   }
} In the code above, a ReadFile class reads from the Grades.txt file. A path is declared, and an InputStream is declared using the Path . In the first indicated line, create the statement to assign a stream to the InputStream reference. In the second indicated line, declare a BufferedReader that reads a line of text from a character-input stream that buffers characters for more efficient reading.