Question 1

Objects saved to an object stream must belong to classes that:
A) implement the Serializable interface.
B) are RandomAccessFile objects.
C) are abstract.
D) implement the ObjectInputStream interface.

Accepted Answer

Objects saved to an object stream must belong to classes that implement the Serializable interface, which signals the Java runtime that the class can be serialized to a stream. This is the only correct answer as options B, C, and D are irrelevant to this context.

Question 2

Objects are saved in ___________ format in object streams.
A) binary
B) character
C) stream
D) integer

Accepted Answer

Objects are saved in binary format in object streams. This is because binary format is a more efficient way to represent and store complex data structures, as it takes up less space and can be read and written faster than other formats. Character, stream and integer formats are not suitable for storing complex object data.

Question 3

Which methods are not in the Serializable interface?
I readObject
II writeObject
III serializeObject
A) I
B) I and II
C) II and III
D) I, II, and III

Accepted Answer

The answer of Which methods are not in the Serializable...

Question 4

When storing numbers in a file with fixed record sizes, it is easier to store them in __________ format.
A) character
B) text
C) binary
D) serializable

Accepted Answer

Storing numbers in binary format takes less space compared to character or text formats. Binary format stores the numbers in the form of bits, which takes up less space and hence can store more numbers in a fixed record size. Additionally, binary format facilitates faster processing and easier retrieval of data compared to text or character formats.

Question 5

Based on the code below, the statement that would move the file pointer to byte n counted from the beginning of the file is ___________________.
RandomAccessFile test = new RandomAccessFile("record.bat", "r");
A) test.getFilePointer(n);
B) test.getFilePointer();
C) test.seek(n);
D) test.length() - n;

Accepted Answer

To move the file pointer to byte n counted from the beginning of the file, we need to use the method seek(n) provided by the RandomAccessFile class. This method sets the file pointer to byte n, which is counted from the beginning of the file. Therefore, option C is the correct statement to use in this scenario. The other options either retrieve the current position of the file pointer or calculate the number of bytes remaining in the file, but they do not move the file pointer to a specific byte location.

Question 6

A file pointer is a position in a random access file. Because files can be very large,
The file pointer is of type _______.
A) double
B) byte
C) int
D) long

Accepted Answer

The file pointer is of type long because it needs to be able to store a large value that represents the current position in the file, which could be at any location in a potentially very large file. The other data types (double, byte, int) are not large enough to handle such values, so long is the best choice.

Question 7

Which interface allows classes to be written to an ObjectOutputStream?
A) Objective
B) Streaming
C) Serializable
D) Objectifiable

Accepted Answer

The Serializable interface allows classes to be written to an ObjectOutputStream, which is used for serialization and deserialization in Java. Option A (Objective) is not a valid Java interface. Option B (Streaming) is too general and doesn't specify the exact interface needed. Option D (Objectifiable) is not a valid Java interface.

Question 8

How many methods are required to implement the Serializable interface?
A) 3
B) 2
C) 1
D) 0

Accepted Answer

The answer of How many methods are required to implement...

Question 9

The readDouble and writeDouble methods of the RandomAccessFile class, process double precision floating-point numbers as ____ quantities.
A) two-byte
B) four-byte
C) eight-byte
D) ten-byte

Accepted Answer

Double precision floating-point numbers are 8-byte quantities, hence the readDouble and writeDouble methods of the RandomAccessFile class process them as 8-byte quantities.

Question 10

If serializing object obj requires 12 bytes, how many bytes are required to serialize obj 3 times?
A) 12 bytes plus 3 serial numbers of obj
B) 36 bytes
C) 12 bytes
D) 12 bytes plus 2 serial numbers of obj

Accepted Answer

The answer of If serializing object obj requires 12 bytes,...

Question 11

Which method moves the file pointer in a RandomAccessFile?
A) seek
B) length
C) getFilePointer
D) close

Accepted Answer

The method "seek" moves the file pointer in a RandomAccessFile to a specified position, allowing for random access to different parts of the file. The other methods listed do not move the file pointer.

Question 12

Which code moves the file pointer to the middle of a RandomAccessFile object, file?
A) file.seek(file.length() / 2)
B) file.seek(file.length())
C) file.seek(0L)
D) file.seek(file.getFilePointer() / 2)

Accepted Answer

The "seek()" method in RandomAccessFile allows us to move the file pointer to a particular byte position in the file. To move the file pointer to the middle of the file, we need to set the pointer to half of the length of the file. Therefore, the correct option is A) file.seek(file.length() / 2).

Question 13

Which of the following cannot be serialized?
I ArrayList<String>
II String
III Integer
A) I
B) II and III
C) III
D) All can be serialized

Accepted Answer

The answer of Which of the following cannot be serialized?
I...

Question 14

Which of these classes access sequences of characters?
I readers
II writers
III streams
A) I
B) II
C) I and II
D) II and III

Accepted Answer

The answer of Which of these classes access sequences of...

Question 15

Use a ____ object to access a file and move a file pointer.
A) Random
B) RandomAccess
C) RandomAccessFile
D) System.in

Accepted Answer

The answer of Use a ____ object to access a...

Question 16

The two IO classes used for serialization are _______ and ________.
A) Reader, Writer
B) ObjectInputStream, ObjectOutputStream
C) Scanner, PrintWriter
D) FileReader, FileWriter

Accepted Answer

ObjectInputStream and ObjectOutputStream are specifically designed for serialization and deserialization of Java objects, while the other classes listed are more general-purpose IO classes that are not specifically intended for serialization. FileReader and FileWriter are specifically designed for reading and writing character-based data, while Reader and Writer are more general-purpose abstract classes for reading and writing character-based data. Scanner and PrintWriter are also more general-purpose classes for reading and writing text-based data.

Question 17

Every object is assigned a serial number on the stream. What might be the result if the same object is saved twice?
A) The object will have two serial numbers.
B) Only the serial number is written out the second time.
C) A performance decrease.
D) Running out of serial numbers.

Accepted Answer

The answer of Every object is assigned a serial number...

Question 18

The readInt and writeInt methods of the RandomAccessFile class read and write integers as ____ quantities.
A) two-byte
B) four-byte
C) six-byte
D) eight-byte

Accepted Answer

The readInt and writeInt methods of the RandomAccessFile class read and write four-byte integers.

Question 19

Which of the following classes are related through inheritance?
I InputStream
II InputStreamReader
III ObjectInputStream
A) I and II
B) I and III
C) II and III
D) I, II and III

Accepted Answer

The answer of Which of the following classes are related...

Question 20

In which package are most classes for file processing found?
A) java.file
B) java.inputoutput
C) java.io
D) java.stream

Accepted Answer

The majority of classes for file processing are found in the java.io package, which includes classes for reading and writing files, as well as for working with input/output streams. The other options mentioned (java.file, java.inputoutput, and java.stream) do not exist as standard packages in Java.

Quiz 19: Streams and Binary Inputoutput

Objects saved to an object stream must belong to classes that:

Objects are saved in ___________ format in object streams.

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

When storing numbers in a file with fixed record sizes, it is easier to store them in __________ format.

Based on the code below, the statement that would move the file pointer to byte n counted from the beginning of the file is ___________________. RandomAccessFile test = new RandomAccessFile("record.bat", "r") ;

A file pointer is a position in a random access file. Because files can be very large, The file pointer is of type _______.

Which interface allows classes to be written to an ObjectOutputStream?

How many methods are required to implement the Serializable interface?

The readDouble and writeDouble methods of the RandomAccessFile class, process double precision floating-point numbers as ____ quantities.

If serializing object obj requires 12 bytes, how many bytes are required to serialize obj 3 times?

Which method moves the file pointer in a RandomAccessFile?

Which code moves the file pointer to the middle of a RandomAccessFile object, file?

Which of the following cannot be serialized? I ArrayList<String> II String III Integer

Which of these classes access sequences of characters? I readers II writers III streams

Use a ____ object to access a file and move a file pointer.

The two IO classes used for serialization are _ and __.

Every object is assigned a serial number on the stream. What might be the result if the same object is saved twice?

The readInt and writeInt methods of the RandomAccessFile class read and write integers as ____ quantities.

Which of the following classes are related through inheritance? I InputStream II InputStreamReader III ObjectInputStream

In which package are most classes for file processing found?