Untitled Quiz

Question 1

• The Collections Framework provides a unified architecture for representing and manipulating collections.

Question 2

• The List interface in the Java Collections Framework represents an ordered collection that can contain duplicate values.

Question 3

• The primary difference between a List and a Set is that a List allows duplicate elements, while a Set does not.

Question 4

• The ArrayList class is typically used to implement a List in the Java Collections Framework.

Question 5

• The Deque interface extends the List interface to provide more efficient insertions and deletions in the middle of the list.

Question 6

• The Map interface in the Java Collections Framework is used to store key-value pairs.

Question 7

• The HashMap class is typically used to implement a Map in the Java Collections Framework.

Question 8

• The TreeMap allows duplicate keys, while a HashMap does not.

Question 9

• The Set interface represents a collection of unique elements with no duplicates.

Question 10

• The HashSet class is typically used to implement a Set in the Java Collections Framework.

Question 11

• LinkedHashSet maintains insertion order, while HashSet does not.

Question 12

• The Collection interface represents a collection of elements with no specific order.

Question 13

• A Queue represents a single-ended queue, while a Deque represents a double-ended queue.

Question 14

• The ArrayDeque class is typically used to implement a Deque in the Java Collections Framework.

Question 15

• The Collections class allows you to create a synchronized (thread-safe) collection.

Question 16

• The SortedSet interface extends the Set interface and represents a collection of elements stored in a sorted order.

Question 17

• The Comparator interface in Java provides methods for comparing objects to enable ordering.

Question 18

• The TreeSet class implements the SortedSet interface.

Question 19

• The Stack interface represents a last-in, first-out (LIFO) stack of elements.

Question 20

• A Stack uses LIFO order, while a Queue uses FIFO order.

Question 21

• The add() method is used to add an element to a collection in the Java Collections Framework.

Question 22

• The toArray() method converts a collection to an array.

Question 23

• The Collections class provides methods to manipulate the size of a list and its elements.

Question 24

• The Iterator interface provides a way to iterate over a collection's elements.

Question 25

• The clear() method removes all elements from a collection.

Question 26

• The Map.Entry interface represents a key-value pair in a map.

Question 27

• The Collections.synchronizedCollection() method obtains a synchronized or thread-safe version of a collection.

Question 28

• HashSet does not maintain insertion order; LinkedHashSet does.

Question 29

• The Collections.synchronizedMap() method is used to make a synchronized map from an existing map.

Question 30

• The Collections.reverse() method reverses the order of elements in a list.

Question 31

• The ensureCapacity() method increases the capacity of an ArrayList object.

Question 32

• The output of the provided Java code snippet is [D, A, B, C].

Question 33

• A Collection in Java is a group of objects.

Question 34

• The singletonList() method converts an object into a List.

Question 35

• The output of the provided Java code snippet is 2.

Question 36

• The premise of equality for IdentityHashMap is reference equality.

Question 37

• The EMPTY_LIST is a static variable defined in Collections.

Question 38

• The addElement() method is used to add elements to a Vector at specific locations.

Question 39

• The output of the provided Java code is 1582.

Question 40

• Stack is LIFO; Queue is FIFO.

Question 41

• The output of the provided Java code is {3, 4}.

Question 42

• Front pointer points to the first element; rear pointer points to the last element

Question 43

• BlockingQueue is a sub-interface of Queue.

Question 44

• trimToSize() method is used to reduce the capacity of an ArrayList object.

Question 45

• Collections.sort(listObj) is used to sort elements of an ArrayList.

Question 46

• The java.util package contains all collection classes.

Question 47

• The keySet() method is used to obtain a set of all keys in a map.

Question 48

• Remote class methods are checkIP(), addLocation(), and AddServer().

Question 49

• The get() method of Map class is used to obtain an element with the specified key.

Question 50

• The elementCount data member of Vector stores the number of elements.

Question 51

• The output of the provided Java code snippet is {A=1, B=2, C=3}.

Question 52

• The java code sample will output the current time and date.

Question 53

• The worst case time complexity of accessing an element in ArrayList is O(1).

Question 54

• The ArrayList class implements a dynamic array.

Question 55

• The enqueue() and dequeue() methods are used to insert and delete items from a queue.

Question 56

• The LinkedList class implements all the standard functions on list data structure.

Question 57

• ConcurrentModificationException is thrown if two threads modify a TreeSet simultaneously.

Question 58

• The output of the provided Java code snippet is Test 10 and Test 10.

Question 59

• The Set interface and HashSet class do not maintain order.

Question 60

• The Enumeration interface is a legacy interface.

Question 61

• The output of the provided Java code snippet is false.

Question 62

• The key is hashed multiple times until the correct bucket is found.

Question 63

• The Collection interface is a basic interface that other interfaces inherit.

Question 64

• The previousIndex() method of ListIterator obtains the index of the previous element.

Question 65

• The output of the provided Java code snippet is [A, D, B, C].

Question 66

• The output of the provided Java code snippet is 12345.

Question 67

• The length() method calculates the number of bits required to hold a BitSet object.

Question 68

• RemoteException is a possible exception thrown by a remote method.

Question 69

• BitSet objects have an architecture similar to arrays.

Question 70

• The sort() method in the Array class sorts the array or its subset.

Question 71

• The output of the program is {A=3, B=2, C=8}.

Question 72

• The Enumeration interface is implemented by Hashtable and Dictionary classes.

Question 73

• The output of the following Java code snippet is 12345.

Question 74

• LinkedHashSet maintains insertion order and ensures uniqueness of elements.

Question 75

• The output of the program is false.

Question 76

• The output of the program is {A=1, B=2, C=3}.

Question 77

• Map class objects use keys to store values.

Question 78

• ArrayList and Vector can be used to create dynamic arrays.

Question 79

• The output of the Java program is 1852.

Question 80

• The output of the Java code snippet is [5, 8, 2, 3, 2].

Question 81

• The output of the provided Java code snippet is 2.

Question 82

• The shuffle() method randomizes elements.

Question 83

• The toArray() method is used to obtain a static array from ArrayList objects.

Question 84

• The put() method inserts a value and its key into a Map.

Question 85

• The clear() method removes all entries from a Map.

Question 86

• The output of the following Java program is "EMPTY".

Question 87

• The output depends on the program to be run.

Question 88

• If a key object already exists in a HashMap, the new object replaces the existing key-value pair.

Question 89

• List and Collection handle sequences.

Question 90

• Collections.synchronizedMap() is used for externally synchronizing HashMap.

Question 91

• Set does have the contains(Object o) method.

Question 92

• HashMap is not a concrete class; HashSet is a concrete class built upon HashMap.

Question 93

• The iterator() method can obtain an iterator to the set's start.

Question 94

• max(Comparator comp) is an incorrect method for max in Java.

Question 95

• The iterator() method is used to obtain an iterator to the start of a Collection.

Question 96

• The output of the program is [1, 3, 4, 8, 9].

Question 97

• The output of the program is 81432

Question 98

• The output of the program is 0

Question 99

• The getProperty() method retrieves elements from a Properties object.

Question 100

• Set has a contains(Object o) method.

Question 101

• HashSet is implemented on top of HashMap.

Question 102

• The return type of the hasNext() method of an iterator is Boolean.

Question 103

• The method iterator() is used to obtain an iterator to the start of a Collection.

Question 104

• The output of the following Java program is [1, 3, 4, 8, 9].

Question 105

• The output of the program is 58881.

Question 106

• The output of the following Java code is 0.

Question 107

• The getProperty() method is used to retrieve elements in the Properties object.

Question 108

• The put() method is used to add elements to a Map.

Question 109

• HashSet<String> listToSet = new HashSet<>(duplicateList); This line of code converts a List into a Set that removes duplicates.

Question 110

• The ListIterator can be used only with a List.

Question 111

• HashMap is not an ordered collection.

Question 112

• Arrays.asList() creates an unmodifiable List, limiting its capacity and preventing the addition or removal of elements.

Question 113

• dequeue() removes and returns the next item, whereas peek() only returns, but does not remove, the next item.

Question 114

• The size() method gets the current size of an ArrayList.

Question 115

• Stack, Hashtable, and Vector are legacy classes.

Question 116

• The initial capacity of HashSet is 16, and the load factor is 0.75.

Question 117

• The output of the Java program will be 2851.

Question 118

• The output will be 1582.

Question 119

• HashSet does not have a get(Object o) method.

Question 120

• LinkedList implements a linked list data structure.

Question 121

• The clear() method deletes all elements from the collection.

Question 122

• Collections.emptySet() returns an immutable set.

Question 123

• The output of the code will be [1=null, 2=null, 3=null, 4=null, 5=null].

Question 124

• The output is 6.

Question 125

• The Map object manages key-value associations.

Question 126

• The output of the program is 1582.

Question 127

• The get() method can be used to retrieve an element in a list.

Question 128

• The remove() method, or using an iterator, is used to eliminate an object from an ArrayList.

Question 129

• The output of the program is 2.

Question 130

• The output of the program will be 54321.

Question 131

• The next() method moves to the next element.

Question 132

• This question is missing from the data.

Question 133

• This question is missing from the data.

Question 134

• The set() method changes an element in a LinkedList.

Question 135

• The output of the Java program is [A, B, C].

Question 136

• The output of the java code is [3,2,6,8].

Question 137

• The output of the java code is {B=2, C=8}

Question 138

• HashSet is a class that implements Set.

Question 139

• SortedList is not a Java collection interface.

Question 140

• The fill() method sets all elements of a collection to a given value.

Question 141

• The Collection interface declares fundamental methods that are commonly used across collections.

Question 142

• SortedSet is an interface, and TreeSet is a class that implements it.

Question 143

• Map is not an interface for Collection.

Question 144

• The output of the program will be 285 1.

Question 145

• The output of this Java code will be a randomized order of the numbers (2, 1, 8, 5).

Question 146

• fill() method in Java's collections framework sets all elements of a list to a given value.

Question 147

• removeLast() is used to delete the last element of a LinkedList.

Question 148

• The add() method is not used in this context, but addFirst() is used to add to the front of a LinkedList.

Question 149

• The output of the java program is [AB, BC, CD].

Question 150

• Vector does not implement the Map interface.

Question 151

• HashMap, and Hashtable are Map implementations.

Question 152

• The get() method is used to obtain an element from BitSet

Question 153

• IllegalStateException can occur from a remove() method in a collection.

Question 154

• The add() method is used to add elements into a HashSet.

Question 155

• The output is 2.

Question 156

• The output is ["A", "D"].

Question 157

• Set interface requires unique elements

Question 158

• size() of ArrayList returns number of elements, and length() is not a valid method for ArrayList.

Question 159

• The rear pointer is updated using the formula rear=(rear+1)%MAX_SIZE to implement a circular queue.

Question 160

• The output of the program is 851.

Question 161-166

• These questions relate to the functionality of the Date class, and Set and Map interfaces.

Question 167

• Maps isn't a Java collection framework interface.

Question 168-171

• These questions deal with Java code packages.

Question 172-176

• These questions involve Java packages and their properties

Question 177

• The java.io package contains classes for handling input and output operations.

Question 178

• The syntax to create a package in Java is package packageName;.

Question 179

• Yes, two packages can have classes with the same name.

Question 180

• java.graphics is not part of the Java standard library.

Question 181

• Use the fully qualified class name to access a class in another package.

Question 182-186

• These questions cover the purpose and functionalities of various Java packages.

Question 187-191

• These questions involve Java threads and their properties.

Question 192-201

• These involve information about various Java threading concepts like wait, notify, join, sleep.

Question 202-206

• These questions deal with thread pools and concepts of concurrency.

Question 127

• binarySearch() is used for searching elements.

Question 109

• For removing duplicates from a List, converting it to a HashSet or using a Set interface is most efficient.