Question 1

Which of the following is not true for the UnsupportedOperationException?

Accepted Answer

It occurs if a method is not found in the underlying collection.

Question 2

Which of the following is a correct difference between ArrayList and LinkedList?

Accepted Answer

ArrayList uses a dynamic array whereas the LinkedList uses doubly linked lis

Question 3

What type of variables can we use with the java.util.Collections Class?

Accepted Answer

reference variables

Question 4

What type of variables can we use with the java.util.Arrays class?
Group of answer choices

both

primitive variables

neither

reference variables

Accepted Answer

both

Question 5

Which of these interface is not a part of Java's collection framework?
Group of answer choices

Set

SortedList

List

SortedMap

Accepted Answer

SortedList

Question 6

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

Accepted Answer

WeakHashMap doesn't allow null keys and null values.

Question 7

Which of the following is not true for a generic collection

Accepted Answer

Generic collection is not mutable.

Question 8

What type of ordering does a PriorityQueue have?
Group of answer choices

ordered and unsorted

unordered and unsorted

ordered and sorted

Accepted Answer

ordered and sorted

Question 9

Which of the following class doesn't implement the Set interface?
Group of answer choices

LinkedHashSet

HashSet

TreeSet

None of the above

Accepted Answer

None of the above

Question 10

A PriorityQueue is always sorted in natural order?
Group of answer choices

false

true

Accepted Answer

false

Question 11

This the standard input stream.
Group of answer choices

System.out

System.in

System.err

Accepted Answer

System.in

Question 12

The java.util.io package contains all the classes required for input and output operations.
Group of answer choices

true

false

Accepted Answer

false

Question 13

In Java, 3 streams are created for us automatically.
Group of answer choices

false

true

Accepted Answer

True

Question 14

A stream is composed of bits
Group of answer choices

false

true

Accepted Answer

false

Question 15

Java In/Ou is used to process the input and produce the output.

Accepted Answer

false

Question 16

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

Accepted Answer

false

Question 17

Java ReadFile class is used to read data from the file.
Group of answer choices

true

false

Accepted Answer

false

Question 18

A constructor of the FileReader class that creates a new file and get its file name in string
Group of answer choices

FileReader (String file)

FileReader (Character file)

FileReader (File file)

FileReader (Byte file)

Accepted Answer

FileReader (String file)

Question 19

write (char c) is a method of the FileWriter class that is used to write the char into FileWriter.
Group of answer choices

true

false

Accepted Answer

True

Question 20

Can we have a sorted and unordered map?
Group of answer choices

Yes

No

Accepted Answer

No

Question 21

When would you choose to use ArrayList over LinkedList in an application?

Accepted Answer

ArrayList is preferred when there is more demand for get via index operations.

Question 22

What type of variables can we use with the java.util.Arrays class?
Group of answer choices

both

reference variables

neither

primitive variables

Accepted Answer

both

Question 23

Which type of list implements the Queue interface
Group of answer choices

ArrayList

LinkedList

Vector

Accepted Answer

LinkedList

Question 24

Which method do we need to implement in the java.util.Comparator interface?
Group of answer choices

sort()

compareTo()

sortTo()

compare()

Accepted Answer

compare()

Question 25

What type of collection does not extend the Collection interface?
Group of answer choices

Map

Queue

Set

List

Accepted Answer

Map

Question 26

Which of the following is a valid difference between Set and Map?

Accepted Answer

Set contains only values whereas Map contains key and values both.

Question 27

Can we have a sorted and unordered set?
Group of answer choices

No

Yes

Accepted Answer

No

Question 28

Which of the following is not true for a fail-fast iterator?

Accepted Answer

Fail fast system reports the failure right away but the system recovers after the failure.

Question 29

Which of the following is not true for a generic collection?
Group of answer choices

Generic collection doesn't require typecasting.

None

Generic collection is typesafe and checked at compile time.

Generic collection is not mutable.

Accepted Answer

Generic collection is not mutable.

Question 30

System.err is the standard error stream.
Group of answer choices

false

true

Accepted Answer

True

Question 31

A stream is a sequence of data.
Group of answer choices

true

false

Accepted Answer

True

Question 32

Java In/Ou is used to process the input and produce the output.
Group of answer choices

false

true

Accepted Answer

False

Question 33

InputStream is used to read data from a source; it may be a file, an array, peripheral device or socket.
Group of answer choices

true

false

Accepted Answer

True

Question 34

InputString is used to read data from a source; it may be a file, an array, peripheral device or socket.
Group of answer choices

true

false

Accepted Answer

False

Question 35

What are the valid Constructors of FileWriter class? (choose two)
Group of answer choices

FileWriter(Byte file)

FileWriter(Character file)

FileWriter(File file)

FileWriter(String file)

Accepted Answer

FileWriter(File file)

FileWriter(String file)

Question 36

A method of the FileReader class that is used to return a character in ASCII form. It returns -1 at the end of file.
Group of answer choices

input ()

get ()

scan ()

read ()

Accepted Answer

read ()

Question 37

flush () is a method of the FileWriter class that is used to close the FileWriter.
Group of answer choices

false

true

Accepted Answer

False

Question 38

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

Question 39

Which of these packages contain all the collection classes?
Group of answer choices

java.net

java.util

java.awt

java.lang

Accepted Answer

java.util

Question 40

Which of these interface declares core method that all collections will have?
Group of answer choices

Comparator

Collection

EventListner

set

Accepted Answer

Collection

Question 41

What is Collection in Java?
Group of answer choices

A group of classes

None of the mentioned

A group of interfaces

A group of objects

Accepted Answer

A group of objects

Question 42

Can we have a sorted and unordered map?
Group of answer choices

Yes

No

Accepted Answer

No

Question 43

Within a PriorityQueue the elements sorted last are processed first?
Group of answer choices

true

false

Accepted Answer

False

Question 44

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

Accepted Answer

HashSet maintains no order while TreeSet maintains ascending order.

Question 45

The __________method of OutputStream Class is used to write an array of byte to the current output stream.

Accepted Answer

write(byte[])

Question 46

Automatically created streams are attached with the console.
Group of answer choices

true

false

Accepted Answer

True

Question 47

A string is a sequence of data.

Accepted Answer

False

Question 48

System.util.Scanner is the standard input stream.

Accepted Answer

False

Question 49

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

Accepted Answer

False

Question 50

scan () 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

False

Question 51

WriterFile(File file) is a constructor of the Filewriter class that creates a new file and get its file name in file objects.
Group of answer choices

false

true

Accepted Answer

False

Question 52

Which interface would we use to sort a class that can't be modified?
Group of answer choices
java.lang.Comparable
java.util.Comparator

Accepted Answer

java.util.Comparator

Question 53

What type of exception is raised when we try run a program with objects that are not mutually comparable in a sorted map?
Group of answer choices
OutOfBoundsException
None
RuntimeException
ClassCastException

Accepted Answer

ClassCastException

Question 54

There are no direct implementation of the Collection interface?

Accepted Answer

True

Question 55

What is returned from both the compare() and compareTo() methods?
Group of answer choices
char
int
boolean
string

Accepted Answer

int

Question 56

Is the following code snippet valid? public class SimpleGenericInterfaceImpl implements SimpleGenericInterface { ?
Group of answer choices
no
yes

Accepted Answer

yes (technically no)

Question 57

What type of collection would we use if we wanted no duplicates?
Group of answer choices
Set
List
Queue
Map

Accepted Answer

Set

Question 58

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 59

What is the correct difference between HashSet and HashMap?

Accepted Answer

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

Question 60

What type of set would you use if you wanted it sorted?
Group of answer choices
HashSet
TreeSet
LinkedHashSet

Accepted Answer

TreeSet

Question 61

All are invalid codes in getting an input from the console, except one.
Group of answer choices
i=System.in.read();
i=System.in.readf("%i",123);
i=System.in.read=123;
i=System.in.readln(123);

Accepted Answer

i=System.in.read();

Question 62

The display(int) method of OutputStream Class is used to write a byte to the current output stream.
Group of answer choices
true
false

Accepted Answer

False, write(int b) or write(byte[] b)

Question 63

System.out is the standard output stream

Accepted Answer

True

Question 64

A method of the FileWriter class that is used to write the string into FileWriter.
Group of answer choices
inscribe (String text)
engrave (String text)
write (String text)
create (String text)

Accepted Answer

write (String text)

OOP LEC [FA5]

CS0070

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