Deck 15: Files, Inputoutput Streams, Nio and Xml Serialization

Question 1

Which of the following is false?

A) JAXB (Java Architecture for XML Binding) enables you to perform XML serialization.
B) Marshaling is the process of deserializing an object.
C) A serialized object is represented by XML that includes the object's data.
D) XML (eXtensible Markup Language) is a widely used language for describing data.

Answer 1

B

Question 2

Which of the following statements is false?

A) Path method isAbsolute returns a boolean indicating whether a Path represents an absolute path to a file or directory.
B) Files static method getLastModifiedTime receives a Path and returns a FileTime (package java.nio.file.attribute) indicating when the file was last modified.
C) Files static method size receives a Path and returns a long representing the number of bytes in the file or directory. For directories, the value returned is platform specific.
D) All of the above are true.

Answer 2

D

Question 3

When all the contents of a file are truncated, this means that ________.

A) the data in the file is saved to a backup file
B) the file is deleted
C) a FileNotFoundException occurs
D) all the data in the file is discarded

Answer 3

all the data in the file is discarded

Question 4

Which statement regarding Java files is false?

A) Java imposes no structure on a file.
B) Notions like "record" do not exist in Java files.
C) The programmer must structure files to meet the requirements of applications.
D) Records in a Java sequential file are stored in order by record key.

Question 5

Which of the following statements is true?

A) Class Scanner provides the ability to reposition to the beginning of a file with method seek.
B) Class Scanner provides the ability to reposition to the beginning of a file with method reposition.
C) Class Scanner does not provide the ability to reposition to the beginning of the file.
D) If it is necessary to read a sequential file again, the program can simply keep reading-when the end of the file is reached, the Scanner is automatically set to point back to the beginning of the file.

Question 6

Which of the following statements is false?

A) Storage of data variables and arrays is temporary.
B) Data is lost when a local variable "goes out of scope."
C) Files are used for long-term retention of large amounts of data.
D) Data maintained in files is often called transient data.

Question 7

Which of the following is false?

A) JAXB works with POJOs (plain old Java objects)-no special superclasses or interfaces are required for XML-serialization support.
B) JAXB serializes only an object's public instance variables and public read-write properties.
C) A class must provide a public default or no-argument constructor to recreate the objects when they're read from the file.
D) JAXB requires you to implement special superclasses and interfaces for XML-serialization support.

Question 8

Path method ________ returns the String name of a file or directory without any location information.

A) getStringName
B) getFileOrDirectoryName
C) getDirectoryName
D) getFileName

Question 9

Which of the following statements is false?

A) A Path represents the location of a file or directory.
B) Path objects open files and provide file-processing capabilities.
C) Class Paths is used to get a Path object representing a file or directory location.
D) The static method get of class Paths converts a String representing a file's or directory's location into a Path object.

Question 10

Files static method ________ receives a Path and returns a boolean indicating whether that Path represents a directory on disk.

A) isDiskDirectory
B) isDirectory
C) isFileDirectory
D) isPath

Question 11

How do methods setIn, setOut and setErr affect the standard input, output and error streams?

A) They output data to the standard input, output and error streams.
B) They provide the only way to access the standard input, output and error streams.
C) They redirect the standard input, output and error streams.
D) They empty the standard input, output and error streams.

Question 12

A(n) ________ path starts from the directory in which the application began executing.

A) absolute
B) relative
C) parallel
D) comparative

Question 13

Class ________ provides static methods for common file and directory manipulations, including methods for copying files; creating and deleting files and directories; getting information about files and directories; reading the contents of files; getting objects that allow you to manipulate the contents of files and directories; and more.

A) File
B) FileAndDirectory
C) Files
D) FilesAndDirectories

Question 14

Which of the following statements is false?

A) A DirectoryStream enables a program to iterate through the contents of a directory.
B) Character-based input and output can be performed with classes Scanner and Formatter.
C) A relative path contains all the directories, starting with the root directory, that lead to a specific file or directory.
D) Every file or directory on a disk drive has the same root directory in its path.

Question 15

What does the following statement do?
Scanner scanner = new Scanner(Paths.get("test.txt"));

A) Opens a binary file for input.
B) Opens a binary file for output.
C) Opens a text file for input.
D) Opens a text file for output.

Question 16

A serialized object is ________.

A) an object represented by XML that includes the object's data.
B) an object in memory that has been recreated from data in a file
C) a standard output stream object used to convert objects in code to data in a file
D) None of the above.

Question 17

The annotation ________ indicates that a private instance variable should be serialized.

A) @XMLElement
B) @Element
C) @Marshal
D) @Serialize

Question 18

Which of the following classes is not used for file input?

A) FileInputStream
B) FileReader
C) ObjectInputStream
D) Formatter

Question 19

Records in a sequential file are not usually updated in place. Instead ________.

A) the updated data is placed in a "surrogate" file
B) the entire file is usually rewritten
C) the file is truncated
D) The above statement is false-records in sequential files are usually updated in place.

Question 20

Streams that input bytes from and output bytes to files are known as ________.

A) bit-based streams
B) byte-based streams
C) character-based streams
D) Unicode-based streams

Question 21

JavaFX classes ________ and ________ (package javafx.stage) display dialogs that enable the user to select a file or directory, respectively.

A) Files, Directories
B) FileChooser, DirectoryChooser
C) FileSelector, DirectorySelector
D) None of the above.

Question 22

The ________ abstract classes are Unicode character-based streams.

A) Reader and Writer
B) BufferedReader and BufferedWriter
C) CharArrayReader and CharArrayWriter
D) UnicodeReader and UnicodeWriter

Question 23

Which of the following statements is false?

A) InputStream and OutputStream are abstract classes for performing byte-based I/O.
B) Tubes are synchronized communication channels between threads.
C) A filter stream provides additional functionality, such as aggregating data bytes into meaningful primitive-type units. FilterInputStream and FilterOutputStream are typically extended, so some of their filtering capabilities are provided by their concrete subclasses.
D) A PrintStream performs text output. System.out and System.err are PrintStreams.

Question 24

________ is an I/O-performance-enhancement technique-it reduces the number of I/O operations by combining smaller outputs together in memory; the number of physical I/O operations is much smaller than the number of I/O requests issued by the program.

A) Aggregating
B) Accumulating
C) Amassing
D) Buffering

Question 25

Which FileChooser method returns the file the user selected?

A) getSelectedFile.
B) getFile.
C) getOpenDialog.
D) showOpenDialog.

Question 26

Which DirectoryChooser method returns the folder the user selected?

A) getSelectedfolder.
B) showDialog.
C) getOpenDialog.
D) showOpenDialog.

Question 27

JAXB's static method ________ deserializes objects from XML.

A) fromXML
B) deserialize
C) unmarshal
D) None of the above

Question 28

JAXB's static method ________ serialize objects as XML.

A) toXML
B) serialize
C) marshal
D) None of the above

Question 29

Which of the following statements is false?

A) A LineNumberReader is a buffered character stream that tracks the number of lines read.
B) Classes FileReader and FileWriter perform character-based file I/O.
C) Class PipedReader and class PipedWriter implement piped-character streams for transferring data between threads.
D) Class StringReader and StringWriter read characters from and write characters to Streams, respectively.

Question 30

Which of the following statements is false?

A) With a BufferedOutputStream each output operation is directed to a buffer large enough to hold the data of many output operations. Transfer to the output device is performed in one large physical output operation when the buffer fills.
B) With a BufferedOutputStream, a partially filled buffer can be forced out to the device at any time by invoking the stream object's force method.
C) With a BufferedInputStream, many "logical" chunks of data from a file are read as one large physical input operation into a memory buffer.
D) With a BufferedInputStream, as a program requests data, it's taken from the buffer. When the buffer is empty, the next actual physical input operation is performed.