Free Java Quiz Questions With Answers - Prepare Yourself For Interviews

All the best for the quiz! - Java Quiz Part 3

Q.1 Which Set class should be most popular in a multi-threading environment, considering performance constraint?

HashSet

ConcurrentSkipListSet

LinkedHashSet

CopyOnWriteArraySet

Q.2 Which Map class should be most popular in a multi-threading environment, considering performance constraint?

Hashtable

CopyOnWriteMap

ConcurrentHashMap

ConcurrentMap

Q.3 Which allows the removal of elements from a collection?

Enumeration

Iterator

Both

None

Q.4 What will be the output of given code -

compile time exception

3 2 1

1 2 3

2 3 1

Q.5 What will be the output of the following code -

1 2 3

1 followed by exception

Compile time exception

Runtime Exception - ClassCastException

Q.6 What will be the output of given code -

a followed by ConcurrentModificationException

a b c

a b

a c

Q.7 What will be the output of given code -

Will execute with none exception

compilation error

Throw ConcurrentModificationException

None of these

Q.8 What will be the output of the following code -

[null, 1]

[1]

[null, 1, 1, null]

Runtime Exception

Q.9 What will be the output of the following code -

{a=ferrari}

{a=audi, a=ferrari}

Runtime Exception

{a=audi}

Q.10 What will be the output of the following code -

Runtime Exception

[1]

[null, 1]

null

Q.11 Which permits the removal of elements from a collection?

Enumeration

Iterator

Both

None

Q.12 The Comparator interface contains the method?

compareWith()

compareTo()

compare()

Q.13 Which of those is synchronized?

TreeMap

HashMap

Hashtable

Q.14 Which is more offers best performance?

TreeMap

HashMap

LinkedHashMap

Q.15 Which of those class ought to be most popular to be used as a key in a very HashMap?
a. String
b. Integer
c. Double

a

b

c

Any of these

Q.16 What should we tend to use once add and remove operations are more frequent than get operations?

LinkedList

ArrayList

Vector

Q.17 Iterator returned by ArrayList is?

Fail-fast

Fail-safe

none

Q.18 Iterator returned by LinkedList is?

Fail-fast

Fail-safe

none

Q.19 Iterator returned by CopyOnWriteArrayList is?

Fail-fast

Fail-safe

none

Q.20 Iterator returned by HashMap on key, value and entry are?

Fail-fast

Fail-safe

none

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Free Java Quiz Questions With Answers – Prepare Yourself For Interviews

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