Collection Quiz in Java - MCQ - Multiple choice questions

Collection Quiz in Java - MCQ - 150 Multiple choice questions in 6 sets




This Quiz consists of Collection's 150 Multiple choice questions in 6 sets - Java Collection quiz - MCQ

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Collection Java - MCQ set 1 (25 questions, 55 marks)
Collection Java - MCQ set 2 (25 questions, 55 marks)
Collection Java - MCQ set 3 (25 questions, 55 marks)
Collection Java - MCQ set 4 (25 questions, 55 marks)
Collection Java - MCQ set 5 (25 questions, 55 marks)
Collection Java - MCQ set 6 (25 questions, 55 marks)







Note : Each set consists of 25 questions
Each set consists of 5 EASY level difficulty questions 1 mark each.         1 * 5 = 5 marks
Each set consists of 10 MEDIUM level difficulty questions 2 mark each. 2 * 10 = 20 marks
Each set consists of 10 HARD level difficulty questions 3 mark each.       3 * 10 = 30 marks
So, each Set is TOTAL of 55 marks
This quiz have been designed to check beginners and experienced Java developers skills.
Scoring below 15 marks means POOR : You are Java Beginner and need to work very hard.
Scoring 15-34 marks means AVERAGE : You know Java basics, but you need more practice.
Scoring 35-50 marks means GOOD : You have good Java knowledge.
Scoring above 50 marks means EXCELLENT : You have outstanding java knowledge.




Collection Java - MCQ set 1 (25 questions, 55 marks)



    Q1 - Q5, 5 EASY level difficulty questions 1 mark each. 1 * 5 = 5 marks

  1. Which of these is not a interface in the Collections Framework?

    2. a.Collection
    b.Group
    c.Set
    d.List

  2. Which interface restricts duplicate elements?

    3. a.Set
    b.List
    c.Map
    d.(All of these)

  3. Which of these collection class has the ability to grow dynamically?

    4. a.Array
    b.Arrays
    c.ArrayList
    d.(None of these)

  4. The accuracy and efficiency of a HashMap can be guaranteed with:

    5. a.override equals method
    b.override hashCode method
    c.(None of these)
    d.(All of these)

  5. A HashMap allows the existence of:

    6. a.null values
    b.one null key
    c.(None of these)
    d.(All of these)



    Q6 - Q15, 10 MEDIUM level difficulty questions 2 mark each. 2 * 10 = 20 marks

  6. What implementation of Iterator can traverse a collection in both directions?

    7. a.Iterator
    b.ListIterator
    c.SetIterator
    d.MapIterator

  7. The Comparable interface contains which called?

    8. a.toCompare
    b.compare
    c.compareTo
    d.compareWith

  8. Which is faster and uses less memory?

    9. a.ListEnumeration
    b.Iterator
    c.Enumeration
    d.ListIterator

  9. What Iterator can throw a ConcurrentModificationException?

    10. a.Fail-fast Iterators
    b.Fail-safe Iterators
    c.(All of these)
    d.(None of these)

  10. What is the default number of Partitions/segments in Concurrent Hash Map?

    11. a.12
    b.32
    c.4
    d.16

  11. Which is best suited to a multi-threaded environment?

    12. a.WeakHashMap
    b.Hashtable
    c.HashMap
    d.ConcurrentHashMap

  12. The default capacity of a Vector is:

    13. a.10
    b.12
    c.8
    d.16

  13. Which does NOT implement the Collection interface?

    14. a.List
    b.Map
    c.Set
    d.(None of these)

  14. The default capacity of a ArrayList is:

    15. a.12
    b.16
    c.1
    d.10

  15. Which provides better performance for the insertion and removal from the middle of the list?

    16. a.Vector
    b.ArrayList
    c.LinkedList
    d.(All of these)



    Q16 - Q25, 10 HARD level difficulty questions 3 mark each.       3 * 10 = 30 marks

  16. What will be output of given code -


    17. a.compile time exception
    b.3 2 1
    c.1 2 3
    d.2 3 1

  17. What will be output of given code -


    18. a.1 2 3
    b.1 followed by exception
    c.Compile time exception
    d.Runtime Exception - ClassCastException

  18. What will be output of given code -


    19. a.a
        followed by ConcurrentModificationException
    b.a b c
    c.a b
    d.a c

  19. An unordered array has a search time complexity of:

    20. a.O(log n)
    b.O(n)
    c.O(n + 1)
    d.O(1)

  20. The add and remove methods of TreeSet have a time complexity of:

    21. a.O(n)
    b.O(n + 1)
    c.O(1)
    d.O(log n)

  21. After resizing, size of ArrayList is increased by :

    22. a.200%
    b.50%
    c.100%
    d.(None of these)

  22. After resizing, size of Vector is increased by:

    23. a.200%
    b.100%
    c.50%
    d.(None of these)

  23. What will be output of given code -


    24. a.will execute without any exception
    b.(None of these)
    c.compilation error
    d.Throw ConcurrentModificationException

  24. Deque and Queue are derived from:

    25. a.AbstractList
    b.Collection
    c.AbstractCollection
    d.List

  25. What will be output of given code -


    26. a.[name=ankit, name=brad]
    b.[name=brad, name=ankit]
    c.Runtime Exception
    d.compile time exception





Quiz 1 - Correct answers



EASY
1) b
2) a
3) c
4) d
5) d

MEDIUM
6) b
7) c
8) c
9) a
10) d
11) d
12) a
13) b
14) d
15) c

HARD
16) b
17) d
18) a
19) b
20) d
21) b
22) b
23) d
24) b
25) a

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Collection Java - MCQ set 2 (25 questions, 55 marks)



    Q1 - Q5, 5 EASY level difficulty questions 1 mark each. 1 * 5 = 5 marks

  1. What guarantees type-safety in a collection?

    2. a.Generics
    b.Abstract classes
    c.Interfaces
    d.Collection

  2. HashSet internally uses?

    3. a.Set
    b.HashMap
    c.List
    d.Collection

  3. The most used interfaces from the Collection framework are?

    4. a.List
    b.Map
    c.Set
    d.(All of these)

  4. The root interface of Java Collection framework hierarchy is -

    5. a.Collection
    b.Root
    c.Collections
    d.List/Set

  5. Which of these is synchronized?

    6. a.ArrayList
    b.LinkedList
    c.Vector
    d.(None of these)



    Q6 - Q15, 10 MEDIUM level difficulty questions 2 mark each. 2 * 10 = 20 marks

  6. ArrayList implements which of the following?

    7. a.List
    b.RandomAccess
    c.Cloneable
    d.(All of these)

  7. Which of these allows the storage of many null values?

    8. a.Set
    b.List
    c.(None of these)
    d.(All of these)

  8. nextIndex() and previousIndex() are methods of which interface?

    9. a.IndexIterator
    b.Iterator
    c.ListIterator
    d.NextPreviousIterator

  9. Vector extends which of these?

    10. a.ArrayList
    b.LinkedList
    c.AbstractList
    d.None

  10. LinkedList implements?

    11. a.Deque
    b.List
    c.None
    d.All

  11. In Iterator, nextElement() method of Enumeration has been changed to:

    12. a.next()
    b.getNext()
    c.returnNext()
    d.name remains same

  12. Enumeration returned by Vector is?

    13. a.fail-fast
    b.fail-safe
    c.none
  13. From Java 5 onwards, which one of these is recommended to replace Hashtable?

    14. a.ConcurrentHashMap
    b.HashMap
    c.ConcurrentHashtable
    d.None

  14. Which does not allow to store a null value?

    15. a.TreeSet
    b.LinkedHashSet
    c.HashSet
    d.None

  15. Iterator returned by Vector is?

    16. a.fail-fast
    b.fail-safe
    c.none



    Q16 - Q25, 10 HARD level difficulty questions 3 mark each.       3 * 10 = 30 marks

  16. What describes how well an algorithm performs in best, average or worse case scenarios?

    17. a.Big-B
    b.Big-O
    c.Big-Data
    d.Big-N

  17. An ordered array has a search time complexity of?

    18. a.O(n)
    b.O(1)
    c.O(log n)
    d.O(n-1)

  18. Which Map class must be preferred in multi-threading environment to maintain natural order of keys?

    19. a.ConcurrentHashMap
    b.ConcurrentSkipListMap
    c.ConcurrentMap
    d.all

  19. What will be output of following code -


    20. a.[null, 1]
    b.[1]
    c.[null, 1, 1, null]
    d.Runtime Exception

  20. What will be output of following code -


    21. a.{a=ferrari}
    b.{a=audi, a=ferrari}
    c.{a=audi}
    d.null

  21. What will be output of following code -


    22. a.{a=ferrari}
    b.{a=audi, a=ferrari}
    c.Runtime Exception
    d.{a=audi}

  22. TreeMap implements?

    23. a.Dictionary
    b.HashMap
    c.AbstractMap
    d.NavigableMap

  23. Which list class must be preferred in multi-threading environment, considering performance constraint

    24. a.Vector
    b.CopyOnWriteArrayList
    c.ArrayList
    d.ConcurrentArrayList

  24. Which Set class must be preferred in multi-threading environment, considering performance constraint

    25. a.HashSet
    b.ConcurrentSkipListSet
    c.LinkedHashSet
    d.CopyOnWriteArraySet

  25. Which Map class must be preferred in multi-threading environment, considering performance constraint

    26. a.Hashtable
    b.CopyOnWriteMap
    c.ConcurrentHashMap
    d.ConcurrentMap





Quiz 2 - Correct answers



EASY
1) a
2) b
3) d
4) a
5) c

MEDIUM
6) d
7) b
8) c
9) c
10) d
11) a
12) b
13) a
14) a
15) a

HARD
16) b
17) c
18) b
19) c
20) a
21) b
22) d
23) b
24) b
25) c

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Collection Java - MCQ set 3 (25 questions, 55 marks)



    Q1 - Q5, 5 EASY level difficulty questions 1 mark each. 1 * 5 = 5 marks

  1. Which allows the removal of elements from a collection?

    2. a.Enumeration
    b.Iterator
    c.Both
    d.None

  2. The Comparator interface contains the method?

    3. a.compareWith()
    b.compareTo()
    c.compare()
    d.

  3. Which of these is synchronized?

    4. a.TreeMap
    b.HashMap
    c.Hashtable
    d.All

  4. Which is more offers best performance?

    5. a.TreeMap
    b.HashMap
    c.LinkedHashMap
    d.All are equal

  5. Which of these class should be preferred to be used as a key in a HashMap?

    6. a.String
    b.Integer
    c.Double
    d.Any of these



    Q6 - Q15, 10 MEDIUM level difficulty questions 2 mark each. 2 * 10 = 20 marks

  6. What should we use when add and remove operations are more frequent than get operations?

    7. a.LinkedList
    b.ArrayList
    c.Vector
    d.All

  7. Iterator returned by ArrayList is?

    8. a.Fail-fast
    b.Fail-safe
    c.none

  8. Iterator returned by LinkedList is?

    9. a.Fail-fast
    b.Fail-safe
    c.none

  9. Iterator returned by CopyOnWriteArrayList is ?

    10. a.Fail-fast
    b.Fail-safe
    c.none

  10. Iterator returned by HashMap on key, value and entry is?

    11. a.Fail-fast
    b.Fail-safe
    c.none

  11. Iterator returned by Hashtable on key, value and entry is?

    12. a.Fail-fast
    b.Fail-safe
    c.none

  12. Iterator returned by ConcurrentHashMap on key, value and entry is?

    13. a.Fail-fast
    b.Fail-safe
    c.none

  13. Iterator returned by LinkedHashMap on key, value and entry is?

    14. a.Fail-fast
    b.Fail-safe
    c.none

  14. Iterator returned by TreeMap on key, value and entry is?

    15. a.Fail-fast
    b.Fail-safe
    c.none

  15. Iterator returned by ConcurrentSkipListMap on key, value and entry is?

    16. a.Fail-fast
    b.Fail-safe
    c.none



    Q16 - Q25, 10 HARD level difficulty questions 3 mark each.       3 * 10 = 30 marks

  16. Which Set implementation is sorted and synchronized?

    17. a.LinkedHashSet
    b.ConcurrentSkipListSet
    c.TreeSet
    d.CopyOnWriteArraySet

  17. TreeMap -

    18. a.doesn't allow null key
    b.allow many null values
    c.All
    d.None

  18. What will be output of following code -


    19. a.{11=a}
    b.{11=a, 12=b}
    c.UnsupportedOperationException
    d.Compile time exception

  19. What will be output of following code -


    20. a.Runtime Exception
    b.Compile time exception
    c.{11=a, null=c}
    d.{11=a, null=null}

  20. What will be output of following code -


    21. a.3
            null
    b.2
            null
    c.1
            null
    d.0
            null

  21. What will be output of following code -


    22. a.1
            null
    b.2
            emp1 OVERRIDDEN
    c.3
            null
    d.1
            emp1 OVERRIDDEN

  22. What will be output of following code -


    23. a.1
            emp1 OVERRIDDEN
    b.2
            emp1 OVERRIDDEN
    c.1
            null
    d.3
            null

  23. What will be output of following code -


    24. a.1
           true
           1
           [1, 3, 4]
    b.3
           true
           1
           [1, 3, 4]
    c.3
           false
           1
           [1, 3, 4]
    d.1
           false
           1
           [1, 2, 4]

  24. Which Map is synchronized?

    25. a.Hashtable
    b.ConcurrentSkipListMap
    c.ConcurrentHashMap
    d.All

  25. concurrentSkipListMap allows

    26. a.one null key
    b.many null values
    c.all
    d.none





Quiz 3 - Correct answers



EASY
1) b
2) c
3) c
4) b
5) d

MEDIUM
6) a
7) a
8) a
9) b
10) a
11) a
12) b
13) a
14) a
15) b

HARD
16) b
17) c
18) b
19) a
20) a
21) c
22) d
23) a
24) d
25) d

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Collection Java - MCQ set 4 (25 questions, 55 marks)



    Q1 - Q5, 5 EASY level difficulty questions 1 mark each. 1 * 5 = 5 marks

  1. What should we use get operations are more?

    2. a.ArrayList
    b.LinkedList
    c.Any

  2. Complexity of ArrayList get method

    3. a.O(n-1)
    b.O(n)
    c.O(1)
    d.O(2n)

  3. Which is sorted by natural order?

    4. a.LinkedHashSet
    b.TreeSet
    c.HashSet
    d.None

  4. Which of these maintains insertion order?

    5. a.List
    b.Set
    c.All
    d.None

  5. Which maintains insertion order?

    6. a.TreeSet
    b.HashSet
    c.LinkedHashSet
    d.None



    Q6 - Q15, 10 MEDIUM level difficulty questions 2 mark each. 2 * 10 = 20 marks

  6. In Iterator, hasMoreElements() method of Enumeration has been changed to:

    7. a.hasNextElement()
    b.isNext()
    c.hasNext()
    d.name remains same

  7. TreeSet internally uses which one to store elements?

    8. a.HashMap
    b.LinkedHashMap
    c.TreeMap
    d.None

  8. HashSet internally uses?

    9. a.HashMap
    b.LinkedHashMap
    c.TreeMap
    d.None

  9. An attempt to add null key to a TreeSet will result in:

    10. a.Will compile
    b.Compile time Exception
    c.Error
    d.Runtime - NullPointerException

  10. What is initial capacity of LinkedList?

    11. a.8
    b.10
    c.16
    d.10

  11. Enumeration returned by ArrayList is

    12. a.Fail-fast
    b.Fail-safe
    c.none

  12. LinkedHashMap allows

    13. a.one null key
    b.many null values
    c.none
    d.all

  13. Hashtable allows

    14. a.one null key
    b.many null values
    c.none
    d.all

  14. How can you sort given HashMap on basis of values

    15. a.Implement Comparator interface and override its compare method
    b.It's not possible
    c.Implement Comparator interface and override its compareTo method
    d.Implement Comparator and Comparable interface

  15. What will be output of following code -


    16. a.1
            null
    b.2
            emp1 OVERRIDDEN
    c.2
            null
    d.1
            emp1 OVERRIDDEN



    Q16 - Q25, 10 HARD level difficulty questions 3 mark each.       3 * 10 = 30 marks

  16. What does Collections.sort internally uses when number of elements are less than 7?

    17. a.Insertion sort
    b.Merge sort
    c.Quick sort
    d.None

  17. What does Collections.sort internally uses when number of elements are greater than 7?

    18. a.Insertion sort
    b.Merge sort
    c.Quick sort
    d.None

  18. An attempt to add null key to a TreeMap will result in:

    19. a.Compile time Exception
    b.Error
    c.Runtime - NullPointerException
    d.None

  19. What will be output of following code -


    20. a.Compile time exception
    b.1
            {null=null}
    c.2
            {11=bmw, null=fer}
    d.Runtime Exception
  20. Which of these is synchronized and doesn't allow null elements?

    21. a.Vector
    b.CopyOnWriteArraySet
    c.CopyOnWriteArrayList
    d.ConcurrentSkipListSet

  21. Which of these is synchronized and isn't sorted by natural order?

    22. a.EnumSet
    b.LinkedList
    c.ConcurrentSkipListSet
    d.Vector

  22. What will be output of following code -


    23. a.11 followed by ConcurrentModificationException
    b.11
    c.ConcurrentModificationException
    d.Compile time exception

  23. What will be output of following code -


    24. a.ind followed by NullPointerException
    b.ind followed by ConcurrentModificationException
    c.ind usa null
    d.ind usa followed by NullPointerException

  24. What will be output of following code -


    25. a.daysEnumMap.get(Days.Monday) : Day1
            daysEnumMap.containsKey(Days.Monday) : true
    b.daysEnumMap.get(Days.Monday) : Day1
            daysEnumMap.containsKey(Days.Monday) : false
    c.Runtime Exception
    d.Compile time exception

  25. In ListIterator, after a call to next() or previous(), if a call is made to set(E element) followed by add() or remove() what happens?

    26. a.compilation error
    b.UnsupportedOperationException
    c.ConcurrentModificationException
    d.none





Quiz 4 - Correct answers



EASY
1) a
2) c
3) b
4) a
5) c

MEDIUM
6) c
7) c
8) a
9) d
10) b
11) a
12) d
13) c
14) a
15) b

HARD
16) a
17) b
18) c
19) c
20) d
21) d
22) b
23) c
24) d
25) b

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Collection Java - MCQ set 5 (25 questions, 55 marks)



    Q1 - Q5, 5 EASY level difficulty questions 1 mark each. 1 * 5 = 5 marks

  1. Which interface must be implemented for sorting on basis many criterias

    2. a.Comparator
    b.Comparable
    c.Serializable
    d.None

  2. Can 2 threads on same ConcurrentHashMap object access it concurrently

    3. a.we need to add additional functionality to achieve the same.
    b.Its not possible
    c.different threads can access different segments concurrently.

  3. What will be output of following code -


    4. a.List l=new ArrayList();
    b.List l=new ArrayList();
    c.List l=new ArrayList();
    d.List l=new ArrayList();

  4. Which of these provides a get(in index) method?

    5. a.Map
    b.Set
    c.List
    d.All

  5. LinkedHashSet implements:

    6. a.Set
    b.Cloneable
    c.Serializable
    d.All



    Q6 - Q15, 10 MEDIUM level difficulty questions 2 mark each. 2 * 10 = 20 marks

  6. What will be output of following code -


    7. a.a
            b
            c
            followed by Exception
    b.Runtime Exception
    c.Compile time exception
    d.a
            b

  7. In WeakHashMap

    8. a.An entry are automatically removed by garbage collector
    b.Behaves normally like HashMap
    c.An entry are never removed by garbage collector
    d.None

  8. A EnumSet

    9. a.Can use enum and non enum type keys
    b.Cannot use enum type keys
    c.is specialized Set implementation for use with enum type keys only
    d.None

  9. Iterator returned by HashSet is

    10. a.Fail-fast
    b.Fail-safe
    c.none

  10. Iterator returned by CopyOnWriteArraySet is

    11. a.Fail-fast
    b.Fail-safe
    c.none

  11. Iterator returned by TreeSet is

    12. a.Fail-fast
    b.Fail-safe
    c.none

  12. Iterator returned by LinkedHashSet is

    13. a.Fail-fast
    b.Fail-safe
    c.none

  13. Iterator returned by ConcurrentSkipListSet is

    14. a.Fail-fast
    b.Fail-safe
    c.none

  14. Which List is synchronized?

    15. a.Vector
    b.CopyOnWriteArrayList
    c.All
    d.none

  15. Which Set is synchronized?

    16. a.CopyOnWriteArraySet
    b.ConcurrentSkipListSet
    c.All
    d.none



    Q16 - Q25, 10 HARD level difficulty questions 3 mark each.       3 * 10 = 30 marks

  16. What will be output of following code -


    17. a.a
            b
            a
            b
    b.a
            b
    c.will print a infinite times
    d.a

  17. What is significance of using instanceOf operator and getClass() in equals method

    18. a.instanceOf will return true for comparing current class with its subclass as well
    b.getClass() will return true only if exactly same class is compared
    c.getClass() will return false when compared with subclass
    d.All

  18. What will be output of following code -


    19. a.11 44
    b.Runtime Exception
    c.Compile time exception
    d.44 11

  19. What will be output of following code -


    20. a.0
            null
    b.1
            null
    c.2
            null
    d.3
            null

  20. What will be output of following code -


    21. a.Compile time exception
    b.a b c d e 1
    c.a b c d e 2
    d.e d c b a -1

  21. What will be output of following code -


    22. a.5
            is WeekDay
            is weekEnd
            true
            0
    b.2
            is WeekDay
            is weekEnd
            true
            0
    c.2
            is WeekEnd
            is weekDay
            true
            0
    d.Compile time exception

  22. What will be output of following code -


    23. a.[1, 1, 2, 3]
    b.[1, 2, 2, 3]
    c.[1, 1, 3, 2]
    d.[1, 2, 3]

  23. What will be output of following code -


    24. a.[{name=amy, id=2}, {name=sam, id=4}]
    b.Runtime Exception
    c.compile time exception
    d.[{name=sam, id=4}, {name=amy, id=2}]

  24. What will be output of following code -


    25. a.[2, 3]
    b.Runtime Exception
    c.compile time exception
    d.None

  25. What will be output of following code -


    26. a.3
    b.3.0
    c.compile time exception
    d.runtime exception





Quiz 5 - Correct answers



EASY
1) a
2) c
3) d
4) c
5) d

MEDIUM
6) d
7) a
8) c
9) a
10) b
11) a
12) a
13) b
14) c
15) c

HARD
16) c
17) d
18) b
19) d
20) d
21) a
22) c
23) d
24) c
25) c

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Collection Java - MCQ set 6 (25 questions, 55 marks)



    Q1 - Q5, 5 EASY level difficulty questions 1 mark each. 1 * 5 = 5 marks

  1. Which of these does NOT have an index based structure?

    2. a.List
    b.Set
    c.Map
    d.

  2. java.util.Collections is a:

    3. a.class
    b.interface
    c.object
    d.none

  3. Methods such as reverse, shuffle and sort are available in:

    4. a.Object
    b.Collection
    c.Collections
    d.Apache Commons Collections

  4. Which of these allows duplicate elements?

    5. a.Set
    b.List
    c.All
    d.None

  5. Which allows the storage of a null key and many null values?

    6. a.Hashtable
    b.HashMap
    c.Both
    d.None



    Q6 - Q15, 10 MEDIUM level difficulty questions 2 mark each. 2 * 10 = 20 marks

  6. What will be output of following code -


    7. a.1
            {null=null}
    b.2
            {null=null, 11=a}
    c.Runtime Exception
    d.Compile time exception

  7. What will be output of following code -


    8. a.1
            2
    b.1
            2
            3
    c.3
            2
            1
    d.ConcurrentModificationException

  8. What will be output of following code -


    9. a.List l=new ArrayList>();
    b.List> l=new ArrayList>();
    c.List l=new ArrayList();
    d.List> l=new ArrayList>();

  9. What will be output of following code -


    10. a.[a, d, b, c]
    b.[a, b, c, d]
    c.[d, a, d, c]
    d.none

  10. What will be output of following code -


    11. a.1
    b.2
    c.0
    d.4

  11. What will be output of following code -


    12. a.{11=audi, null=null}
    b.{null=null}
    c.{11=bmw, null=fer}
    d.Runtime Exception

  12. What will be output of following code -


    13. a.[]
    b.[{name=sam, id=4}, {name=amy, id=2}]
    c.[{name=amy, id=2}, {name=sam, id=4}]
    d.[null]

  13. What will be output of following code -


    14. a.1 2 1.1 2.2
    b.Runtime Exception
    c.compile time exception
    d.None

  14. What will be output of following code -


    15. a.5.0
    b.5
    c.Runtime Exception
    d.compile time exception

  15. What will be output of following code -


    16. a.3
            null
    b.1
            emp1 OVERRIDDEN
    c.2
            emp1 OVERRIDDEN
    d.3
            emp1 OVERRIDDEN



    Q16 - Q25, 10 HARD level difficulty questions 3 mark each.       3 * 10 = 30 marks

  16. What will be output of following code -


    17. a.[3, 2, 1]
    b.compile time exception
    c.Runtime Exception
    d.[1, 2, 3]

  17. What will be output of following code -


    18. a.[1, 2, 3]
    b.Runtime Exception - classCastException
    c.[3, 2, 1]
    d.None

  18. What will be output of following code -


    19. a.[3, 2, 1]
    b.Runtime Exception - NullPointerException
    c.[1, 2, 3]
    d.Runtime Exception - classCastException

  19. What will be output of following code -


    20. a.{4=1, 3=1, 2=1}
    b.{2=1, 3=1, 4=1}
    c.{4=1, 2=1, 3=1}
    d.compile time exception

  20. What will be output of following code -


    21. a.Runtime Exception
    b.412
    c.124
    d.421

  21. What will be output of following code -


    22. a.542
    b.245
    c.425
    d.None

  22. What will be output of following code -


    23. a.Runtime Exception - NullPointer
    b.Runtime Exception - IndexOutOfBound
    c.compile time error
    d.23

  23. What will be output of following code -


    24. a.IndexOutOfBoundException
    b.23
    c.compile time error
    d.NullPointerException

  24. In ConcurrentHashMap - When thread locks one segment for updation it does not block it for retrieval hence some other thread can read the same segment, but it will be able to read the data before locking?

    25. a.true
    b.false
    c.may be true/false
  25. In ConcurrentHashMap - When thread locks one segment for updation it does not allow any other thread to perform updations in same segment until lock is not released on segment

    26. a.true
    b.false
    c.may be true/false




Quiz 6 - Correct answers



EASY
1) b
2) a
3) c
4) b
5) b

MEDIUM
6) b
7) d
8) d
9) a
10) b
11) d
12) c
13) a
14) a
15) b

HARD
16) b
17) a
18) b
19) a
20) b
21) a
22) d
23) c
24) a
25) a

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