Question 1

How many ways does the java.lang.Comparable interface allow us to sort a collection?

Accepted Answer

1

Question 2

Which of these is Basic interface that all other interface inherits?

Accepted Answer

Collection

Question 3

vWhich of these methods sets every element of a List to a specified object?

Accepted Answer

fill()

Question 4

What type of List is used with synchronized access?

Accepted Answer

Vector

Question 5

Which of these is an incorrect form of using method max() to obtain maximum element?

Accepted Answer

max(Comparator comp)

Question 6

Which of the following class doesn't implement the Set interface?

Accepted Answer

None of the above

Question 7

What is the correct difference between HashSet and HashMap?

Accepted Answer

HashSet contains only values whereas HashMap contains the key and value pair.

Question 8

A PriorityQueue is always sorted in natural order?

Accepted Answer

false

Question 9

Which of the following is not true for a generic collection?

Accepted Answer

Generic collection is not mutable.

Question 10

Which of the following is a correct difference between HashMap and Hashtable?

Accepted Answer

HashMap is not synchronized while the Hashtable is synchronized.

Question 11

The display(byte[]) method of OutputStream Class is used to write an array of byte to the current output stream.

Accepted Answer

False

Question 12

System.err is the standard error stream.

Accepted Answer

true

Question 13

In Java, 3 streams are created for us automatically.

Accepted Answer

true

Question 14

A stream is a sequence of data.

Accepted Answer

True

Question 15

An _________ accepts output bytes and sends them to some sink.

Accepted Answer

OutputStream

Question 16

A method of the FileWriter class that is used to write char array into FileWriter.

Accepted Answer

write(char[] c)

Question 17

The FileReader (String file) is the constructor of the FileReader class that creates a new file and get its file name in string

Accepted Answer

false

Question 18

write (char c) is a method of the FileWriter class that is used to write the char into FileWriter.

Accepted Answer

True

Question 19

A method of the FileWriter class that is used to close the FileWriter.

Accepted Answer

close()

Question 20

A method of the FileWriter class that is used to write the char into FileWriter.

Accepted Answer

write (char c)

Question 21

Which of these interface is not a part of Java's collection framework?

Accepted Answer

SortedList

Question 22

We can use any object with the methods of the java.util.Arrays class?

Accepted Answer

Yes

Question 23

We can use any object with the methods of the java.util.Arrays class?

Accepted Answer

No

Question 24

Which of these interface declares core method that all collections will have?

Accepted Answer

Collection

Question 25

Which of these methods deletes all the elements from invoking collection?

Accepted Answer

clear()

Question 26

What type of set would you use if you wanted it sorted?

Accepted Answer

TreeSet

Question 27

Which of the following is a correct difference between List and Set?

Accepted Answer

List can hold duplicate elements while Set includes only unique elements.

Question 28

What is the design pattern followed by Iterator?

Accepted Answer

None

Question 29

InputString is used to read data from a source; it may be a file, an array, peripheral device or socket.

Accepted Answer

true

Question 30

It is the superclass of all classes representing an output stream of bytes.

Accepted Answer

OutputStream

Question 31

The erase() method of OutputStream Class flushes the current output stream.

Accepted Answer

false

Question 32

An output stream accepts output bytes and sends them to some sink.

Accepted Answer

true

Question 33

flush() is a method of the FileWriter class that flushes the data of FileWriter.

Accepted Answer

true

Question 34

create (char[] c) is a method of the FileWriter class that is used to write char array into FileWriter.

Accepted Answer

false

Question 35

Java FileReader class returns data in byte format like FileInputStream class.

Accepted Answer

true

Question 36

WriterFile(String file) is a constructor of the Filewriter class that creates a new file and get its file name in string

Accepted Answer

false

Question 37

A constructor of the Filewriter class that creates a new file and get its file name in string

Accepted Answer

FileWriter(String file)

Question 38

Which method do we need to implement in the java.util.Comparator interface?

Accepted Answer

compare()

Question 39

Which method do we need to implement in the java.lang.Comparable interface?

Accepted Answer

compareTo()

Question 40

If two arrays hold the same elements they are considered equal by the Arrays.equals() method?

Accepted Answer

false

Question 41

Which type of list implements the Queue interface

Accepted Answer

LinkedList

Question 42

You can't put null elements into Queues in the API?

Accepted Answer

true

Question 43

What type of ordering does a PriorityQueue have?

Accepted Answer

ordered and sorted

Question 44

What type of Queue is a PriorityQueue?

Accepted Answer

PIPO

Question 45

Which of the following is a correct difference between HashSet and TreeSet?

Accepted Answer

HashSet maintains no order while TreeSet maintains ascending order.

Question 46

All are invalid codes in getting an input from the console, except one.

Accepted Answer

i=System.in.read();

Question 47

InputStream is used to read data from a source; it may be a file, an array, peripheral device or socket.

Accepted Answer

true

Question 48

System.in is the standard input stream.

Accepted Answer

true

Question 49

The write(int) method of OutputStream Class is used to write a byte to the current output stream.

Accepted Answer

true

Question 50

What are the valid Constructors of FileReader class? (choose two)

Accepted Answer

FileReader (String file)
FileReader (File file)

Question 51

read () is a method of the FileReader class that is used to return a character in ASCII form. It returns 0 at the end of file.

Accepted Answer

false

Question 52

create (char c) is a method of the FileWriter class that is used to write the char into FileWriter.

Accepted Answer

false

Question 53

Java FileReader class is used to read data from the file.

Accepted Answer

true

Question 54

Is the following code snippet valid?

 

 

List aList = new ArrayList();

Accepted Answer

yes

Question 55

Which of the following is a benefit of using the Java Collections Framework?

Accepted Answer

More robust codebase

Question 56

Which of these classes is not part of Java's collection framework?

Accepted Answer

Array

Question 57

What do sets care about

Accepted Answer

Uniqueness

Question 58

Which of the following is not true in case of a WeakHashMap?

Accepted Answer

WeakHashMap doesn't allow null keys and null values.

Question 59

Automatically created streams are attached with the console.

Accepted Answer

true

Question 60

The ________ method of OutputStream Class flushes the current output stream.

Accepted Answer

flush()

Question 61

A string is a sequence of data.

Accepted Answer

true

Question 62

read () is a method of the FileReader class that is used to return a character in ASCII form. It returns -1 at the end of file.

Accepted Answer

true

Question 63

In using FileWriter class, unlike FileOutputStream class, you don't need to convert string into byte array because it provides method to write string directly.

Accepted Answer

true

Question 64

In using __________, unlike FileOutputStream class, you don't need to convert string into byte array because it provides method to write string directly.

Accepted Answer

FileWriter class

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OOP MOD 9&10