Question 1

Fill in the blank in the following code snippet that displays the names of directories in the current directory.

Accepted Answer

A) Files.isDirectory(p) 
B) isDirectory(p) 
C) p.isDirectory() 
D) Paths.isDirectory(p) 
A) Files.isDirectory(p) 
B) isDirectory(p) 
C) p.isDirectory() 
D) Paths.isDirectory(p)

Question 2

Assume we have a RandomAccessFile object, file, which stores a set of records of class MyData, each needing MyData.RECORD_SIZE bytes for storage.If the file pointer is currently on the 24th record, which expression represents the offset to the beginning of the 25th record?

Accepted Answer

A) MyData.RECORD_SIZE * 2 
B) MyData.RECORD_SIZE + file.getFilePointer() 
C) MyData.RECORD_SIZE + 1 
D) file.getFilePointer() 
A) MyData.RECORD_SIZE * 2 
B) MyData.RECORD_SIZE + file.getFilePointer() 
C) MyData.RECORD_SIZE + 1 
D) file.getFilePointer()

Question 3

Which expression deletes the file named filename.txt?

Accepted Answer

A) Files.delete(Paths.get("filename.txt")) 
B) Files.deleteFile(Paths.get("filename.txt")) 
C) Files.deleteFile("filename.txt") 
D) Files.delete("filename.txt") 
A) Files.delete(Paths.get("filename.txt")) 
B) Files.deleteFile(Paths.get("filename.txt")) 
C) Files.deleteFile("filename.txt") 
D) Files.delete("filename.txt")

Question 4

Which methods are not in the Serializable interface?
i.readObject
II.writeObject
III.serializeObject

Accepted Answer

A) II and III only 
B) I, II, and III 
C) I and II only 
D) I only 
A) II and III only 
B) I, II, and III 
C) I and II only 
D) I only

Question 5

A Caesar cipher uses a shift of each character by a key with a value between 1 and 255.An a with a shift of 3 becomes a d.For the encrypt method below, select the correct body.Assume the key shift property is accessible to the method.
public int encrypt(int b)
{
__________
}

Accepted Answer

A) return (b + key) % 256); 
B) return (b + key % 26); 
C) return (b + key); 
D) return (b + 26 % key); 
A) return (b + key) % 256); 
B) return (b + key % 26); 
C) return (b + key); 
D) return (b + 26 % key);

Question 6

Which of the following is NOT a method of the Files class?

Accepted Answer

A) readAllBytes 
B) write 
C) readAllLines 
D) read 
A) readAllBytes 
B) write 
C) readAllLines 
D) read

Question 7

Fill in the blank in the following code snippet that displays the directory structure for the current directory, i.e., including the descendants of the current directory that are directories.

Accepted Answer

A) Stream listing = Files.list(Paths.get("")) B) Stream listing = Files.walk(Paths.get("")) C) Stream listing = Files.walk(Paths.get("")) D) Stream listing = Files.walk("") A) Stream listing = Files.list(Paths.get("")) B) Stream listing = Files.walk(Paths.get("")) C) Stream listing = Files.walk(Paths.get("")) D) Stream listing = Files.walk("")

Question 8

Which interface allows classes to be written to an ObjectOutputStream?

Accepted Answer

A) Streaming 
B) Serializable 
C) Objectifiable 
D) Objective 
A) Streaming 
B) Serializable 
C) Objectifiable 
D) Objective

Question 9

Fill in the blank in the following code snippet that filters log warning messages to a file.

Accepted Answer

A) Files.write("warnings.txt", warnings); 
B) Files.writeAllLines(Paths.get("warnings.txt"), warnings); 
C) Files.writeAllBytes(Paths.get("warnings.txt"), warnings.getBytes("UTF-8")); 
D) Files.write(Paths.get("warnings.txt"), warnings); 
A) Files.write("warnings.txt", warnings); 
B) Files.writeAllLines(Paths.get("warnings.txt"), warnings); 
C) Files.writeAllBytes(Paths.get("warnings.txt"), warnings.getBytes("UTF-8")); 
D) Files.write(Paths.get("warnings.txt"), warnings);

Question 10

If you store information in binary form, as a sequence of bytes, you will use the ____ class(es) and their subclasses.

Accepted Answer

A) Reader and Writer 
B) PrintWriter 
C) Serializable 
D) InputStream and OutputStream 
A) Reader and Writer 
B) PrintWriter 
C) Serializable 
D) InputStream and OutputStream

Question 11

The read method of the FileInputStream class reads binary data.What type is actually returned from a call to read?

Accepted Answer

A) int 
B) String 
C) byte 
D) char 
A) int 
B) String 
C) byte 
D) char

Question 12

A Caesar cipher uses a shift of each character by a key with a value between 1 and 255.An a with a shift of 3 becomes a d.A z with a shift of 3 would become a c, wrapping around the alphabet.Which is the decryption of exmmv for a key = -3?

Accepted Answer

A) bujjs 
B) atiir 
C) cvkkt 
D) happy 
A) bujjs 
B) atiir 
C) cvkkt 
D) happy

Question 13

Which class is used for output of text data?

Accepted Answer

A) OutputStream 
B) Reader 
C) InputStream 
D) Writer 
A) OutputStream 
B) Reader 
C) InputStream 
D) Writer

Question 14

Which method in the RandomAccessFile class provides for random access?

Accepted Answer

A) goto 
B) offset 
C) seek 
D) move 
A) goto 
B) offset 
C) seek 
D) move

Question 15

What is the highest value for a signed (negative and positive) byte?

Accepted Answer

A) 256 
B) 127 
C) 128 
D) 255 
A) 256 
B) 127 
C) 128 
D) 255

Question 16

Which class is used for input of text data?

Accepted Answer

A) OutputStream 
B) Writer 
C) InputStream 
D) Reader 
A) OutputStream 
B) Writer 
C) InputStream 
D) Reader

Question 17

A Caesar cipher uses a shift of each character by a key with a value between 1 and 255.An a with a shift of 3 becomes a d.A z with a shift of 3 would become a c, wrapping around the alphabet.Which key should you use to encrypt picture into mfzqrob?

Accepted Answer

A) 19 
B) -3 
C) -19 
D) 3 
A) 19 
B) -3 
C) -19 
D) 3

Question 18

A Caesar cipher uses a shift of each character by a key with a value between 1 and 255.An a with a shift of 3 becomes a d.A z with a shift of 3 would become a c, wrapping around the alphabet.Which is the encryption of picture for a key = -3?

Accepted Answer

A) mfzqrob 
B) erutcip 
C) urepict 
D) ngahspc 
A) mfzqrob 
B) erutcip 
C) urepict 
D) ngahspc

Question 19

Which class is used for input of text data from a file?

Accepted Answer

A) FileWriter 
B) RandomAccessFile 
C) FileInputStream 
D) Scanner 
A) FileWriter 
B) RandomAccessFile 
C) FileInputStream 
D) Scanner

Question 20

Which statement reads the configuration file named config.txt into a collection for later processing?

Accepted Answer

A) List configData = Files.read(Paths.get("config.txt")); B) List configData = Files.readAllBytes(Paths.get("config.txt")); C) List configData = Files.readAllLines("config.txt"); D) List configData = Files.readAllLines(Paths.get("config.txt")); A) List configData = Files.read(Paths.get("config.txt")); B) List configData = Files.readAllBytes(Paths.get("config.txt")); C) List configData = Files.readAllLines("config.txt"); D) List configData = Files.readAllLines(Paths.get("config.txt"));

Exam 21: Advanced Input/Output

Fill in the blank in the following code snippet that displays the names of directories in the current directory.

Assume we have a RandomAccessFile object, file, which stores a set of records of class MyData, each needing MyData.RECORD_SIZE bytes for storage.If the file pointer is currently on the 24th record, which expression represents the offset to the beginning of the 25th record?

Which expression deletes the file named filename.txt?

Which methods are not in the Serializable interface? i.readObject II.writeObject III.serializeObject

A Caesar cipher uses a shift of each character by a key with a value between 1 and 255.An a with a shift of 3 becomes a d.For the encrypt method below, select the correct body.Assume the key shift property is accessible to the method. public int encrypt(int b) { __________ }

Which of the following is NOT a method of the Files class?

Fill in the blank in the following code snippet that displays the directory structure for the current directory, i.e., including the descendants of the current directory that are directories.

Which interface allows classes to be written to an ObjectOutputStream?

Fill in the blank in the following code snippet that filters log warning messages to a file.

If you store information in binary form, as a sequence of bytes, you will use the ____ class(es) and their subclasses.

The read method of the FileInputStream class reads binary data.What type is actually returned from a call to read?

A Caesar cipher uses a shift of each character by a key with a value between 1 and 255.An a with a shift of 3 becomes a d.A z with a shift of 3 would become a c, wrapping around the alphabet.Which is the decryption of exmmv for a key = -3?

Which class is used for output of text data?

Which method in the RandomAccessFile class provides for random access?

What is the highest value for a signed (negative and positive) byte?

Which class is used for input of text data?

A Caesar cipher uses a shift of each character by a key with a value between 1 and 255.An a with a shift of 3 becomes a d.A z with a shift of 3 would become a c, wrapping around the alphabet.Which key should you use to encrypt picture into mfzqrob?

A Caesar cipher uses a shift of each character by a key with a value between 1 and 255.An a with a shift of 3 becomes a d.A z with a shift of 3 would become a c, wrapping around the alphabet.Which is the encryption of picture for a key = -3?

Which class is used for input of text data from a file?

Which statement reads the configuration file named config.txt into a collection for later processing?

Introduction

Using Objects

Implementing Classes

Fundamental Data Types

Decisions

Loops

Arrays and Array Lists

Designing Classes

Inheritance

Interfaces

Input/Output and Exception Handling

Object-Oriented Design

Recursion

Sorting and Searching

The Java Collections Framework

Basic Data Structures

Tree Structures

Generic Classes

Stream Processing

Graphical User Interfaces

Multithreading

Internet Networking

Relational Databases

XML

Filters