Question 1

Adding the services of one stream to another is known as ________.
A) chaining
B) wrapping
C) adding
D) sequencing

Accepted Answer

B

Question 2

What interface must a class implement to indicate that objects of the class can be output and input as a stream of bytes?
A) Synchronize
B) Deserializable
C) Serializable
D) ObjectOutput

Accepted Answer

The Serializable interface must be implemented by a class to indicate that objects of the class can be serialized, meaning they can be converted into a stream of bytes for storage or transmission. This allows the objects to be easily transported between different networks or platforms. The other options listed (Synchronize, Deserializable, ObjectOutput) are not relevant to this functionality.

Question 3

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.

Accepted Answer

The statement creates a new Scanner object to read from the text file named "test.txt" using the Paths.get() method. Therefore, the correct option is to open a text file for input.

Question 4

Path method ________ returns the String name of a file or directory without any location information.
A) getStringName
B) getFileOrDirectoryName
C) getDirectoryName
D) getFileName

Accepted Answer

The getFileName() method returns the String name of a file or directory without any location information.

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.

Accepted Answer

Class Scanner does not provide the ability to reposition to the beginning of the file.

Question 6

Instance variables that are not to be output with a Serializable object are declared using which keyword?
A) private
B) ignoreme
C) transient
D) persistent

Accepted Answer

The keyword "transient" is used to declare instance variables that should not be serialized with a Serializable object. This means that their values will not be saved and loaded with the object when it is written to and read from a stream. Private, ignoreme, and persistent are not keywords that have any special meaning in serialization.

Question 7

________ path starts from the directory in which the application began executing.
A) absolute
B) relative
C) parallel
D) comparative

Accepted Answer

A relative path is a file path that is relative to the current working directory of the program, which is the directory in which the application began executing. This means that a relative path will only work correctly if the program is executed from the same directory every time.

Question 8

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.

Accepted Answer

Path objects represent the location of a file or directory and can be used to manipulate paths and retrieve information about files and directories. However, they do not open files or provide file-processing capabilities. That functionality is provided by classes such as FileInputStream and BufferedReader.

Question 9

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

Accepted Answer

Byte-based streams are designed to input and output bytes from and to files. Bit-based streams deal with individual bits, character-based streams deal with characters, and Unicode-based streams deal with Unicode characters.

Question 10

A serialized object is ________.
A) an object represented as a sequence of bytes used to store the object's data in a file
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.

Accepted Answer

A serialized object is an object represented as a sequence of bytes used to store the object's data in a file. This process is known as serialization. The serialized object can then be deserialized, or re-created as an object in memory, from the data in the file. Option B describes a deserialized object while Option C describes the function of ObjectOutputStream and not the serialized object itself. Option D is a clear incorrect statement.

Question 11

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.

Accepted Answer

A relative path specifies a location starting from the current directory and does not need to start from the root directory. Absolute paths, not relative paths, start with the root directory.

Question 12

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.

Accepted Answer

Java does not inherently support the concept of records stored in order by a record key within its file system operations. The handling of how data is structured, including any sorting or ordering, is up to the programmer to implement in their application code. Java files themselves are treated as streams of bytes, and any notion of records or their ordering is a higher-level abstraction not provided by the Java file I/O APIs directly.

Question 13

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.

Accepted Answer

Data maintained in files is often referred to as persistent because it is intended to be preserved and used for long-term retention, unlike transient data, which is short-term and temporary.

Question 14

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.

Accepted Answer

Records in a sequential file are not usually updated in place. Instead, the entire file is usually rewritten. This is because sequential files are typically stored on physical media in contiguous blocks, making it difficult to insert or delete data within the file without rewriting the entire file. Therefore, instead of updating a single record in the file, the entire file is rewritten with the updated record included in its appropriate position.

Question 15

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.

Accepted Answer

The methods setIn, setOut and setErr redirect the standard input, output and error streams respectively. So, the correct choice is C.

Question 16

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

Accepted Answer

Truncating a file means removing all the data from it, so option D - "all the data in the file is discarded" is the correct answer. There is no mention of saving the data to a backup file, deleting the file, or a FileNotFoundException occurring.

Question 17

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

Accepted Answer

The correct answer is C) Files. The java.nio.file.Files class provides static methods for various file and directory operations, such as copying, creating, deleting, and reading files, as well as getting information about them.

Question 18

Which of the following classes is not used for file input?
A) FileInputStream
B) FileReader
C) ObjectInputStream
D) Formatter

Accepted Answer

Formatter is used for formatting and outputting data, not for file input. FileInputStream, FileReader, and ObjectInputStream are all used for reading data from files.

Question 19

Which of the following classes enable input and output of entire objects to or from a file?
A. SerializedInputStream
B. SerializedOutputStream
C. ObjectInputStream
D. ObjectOutputStream
E. Scanner
F.Formatter
A) A and B.
B) C and D.
C) C, D, E, F.
D) E and F.

Accepted Answer

ObjectInputStream and ObjectOutputStream enable input and output of entire objects to or from a file through serialization. SerializedInputStream and SerializedOutputStream are not valid classes in Java. Scanner and Formatter are used for input and output of text-based data, but not for objects.

Question 20

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

Accepted Answer

The correct static method to check whether a Path represents a directory on disk is Files.isDirectory(Path path). Therefore, the best choice is B.

Quiz 15: Files, Streams and Object Serialization

Adding the services of one stream to another is known as ________.

What interface must a class implement to indicate that objects of the class can be output and input as a stream of bytes?

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

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

Which of the following statements is true?

Instance variables that are not to be output with a Serializable object are declared using which keyword?

________ path starts from the directory in which the application began executing.

Which of the following statements is false?

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

A serialized object is ________.

Which of the following statements is false?

Which statement regarding Java files is false?

Which of the following statements is false?

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

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

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

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

Which of the following classes enable input and output of entire objects to or from a file? A. SerializedInputStream B. SerializedOutputStream C. ObjectInputStream D. ObjectOutputStream E. Scanner F.Formatter

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