Question 1

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

Readers and writers are classes that access sequences of characters, with readers being used for reading character streams and writers for writing character streams. Streams, in general, can be for bytes or characters, but the question specifically asks for sequences of characters.

Question 2

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 3

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

Accepted Answer

The RandomAccessFile object in Java allows you to access a file and move the file pointer to read or write data at any position within the file.

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

Binary format is more efficient for fixed record sizes as it allows for direct storage of numerical data without conversion to text, saving space and improving access speed.

Question 5

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 handle integers as four-byte quantities, which corresponds to the size of an int in Java.

Question 6

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 the IO classes specifically designed for serialization and deserialization of objects in Java.

Question 7

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, which allows for the serialization and deserialization of objects in Java.

Question 8

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

Accepted Answer

The Serializable interface is a marker interface in Java, which means it does not contain any methods that need to be implemented.

Question 9

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

The `seek(n)` method is used to move the file pointer to a specific byte position `n` from the beginning of the file in a `RandomAccessFile` object.

Question 10

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

The readDouble and writeDouble methods of the RandomAccessFile class process double precision floating-point numbers as eight-byte quantities, which is the standard size for a double in Java.

Question 11

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 12

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

Accepted Answer

The Serializable interface in Java is used to enable classes to be written to an ObjectOutputStream, allowing objects to be serialized.

Question 13

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 implement the Serializable interface to allow their state to be converted into a byte stream.

Question 14

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

Accepted Answer

The seek method is used to move the file pointer to a specified position in a RandomAccessFile.

Question 15

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 method `file.seek(file.length() / 2)` correctly moves the file pointer to the middle of the file by dividing the total length of the file by 2.

Question 16

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

InputStream is a superclass of ObjectInputStream, meaning ObjectInputStream inherits from InputStream. InputStreamReader, however, does not inherit from InputStream; it is a bridge from byte streams to character streams.

Question 17

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 handle large file sizes, which may exceed the range of an int.

Question 18

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

All the given options can be serialized in Java as they all implement the Serializable interface.

Question 19

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 Serializable interface does not contain any methods. It is a marker interface used to indicate that a class can be serialized. Methods like readObject and writeObject are not part of the Serializable interface; they are part of the serialization mechanism but not defined in the interface itself. serializeObject is not a standard method in Java serialization.

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 java.io package contains most of the classes required for input and output operations, including file processing in Java.

Quiz 20: Streams and Binary Inputoutput

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

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

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

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

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

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

Objects are saved in ___________ format in object streams.

How many methods are required to implement the Serializable interface?

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") ;

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

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

Which interface allows classes to be written to an ObjectOutputStream?

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

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 classes are related through inheritance? I InputStream II InputStreamReader III ObjectInputStream

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

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

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

In which package are most classes for file processing found?