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Java Quiz Day 41
Question 1
Which method of the Iterator interface removes the last element returned by the iterator?
- A
delete()
- B
remove()
- C
clear()
- D
discard()
Question 2
What happens if you modify a collection directly while iterating over it using a normal Iterator?
- A
It updates automatically
- B
Throws ConcurrentModificationException
- C
Skips modified elements
- D
The iterator restarts
Question 3
Which iterator type allows iteration in both directions in Java?
- A
Iterator
- B
Enumeration
- C
CollectionIterator
- D
ListIterator
Question 4
If a class implements Comparable, which method must it override?
- A
equals(Object obj)
- B
compareTo(Object o)
- C
compare(Object o1, Object o2)
- D
hashCode()
Question 5
Which statement is TRUE about Comparator in Java?
- A
A comparator is used to define the natural ordering of objects.
- B
Comparator is implemented inside the class itself.
- C
Comparator can be used to define multiple sorting orders.
- D
Comparator can only sort Strings.
Question 6
In Comparable, the compareTo() method should return:
- A
Positive integer if current object is less than the specified object
- B
Zero if current object is greater
- C
Negative integer if current object is greater
- D
Positive integer if current object is greater than the specified object
Question 7
Which class from java.util.concurrent allows a thread to safely wait for another thread's completion?
- A
Semaphore
- B
CountDownLatch
- C
CyclicBarrier
- D
All of the above
Question 8
Which concurrent collection is best suited for a producer-consumer scenario?
- A
CopyOnWriteArrayList
- B
ConcurrentHashMap
- C
LinkedBlockingQueue
- D
ConcurrentSkipListMap
Question 9
Which concurrent collection maintains elements in a sorted order?
- A
ConcurrentHashMap
- B
CopyOnWriteArrayList
- C
ConcurrentSkipListSet
- D
ConcurrentLinkedQueue
Question 10
Which concurrent collection is an unbounded thread-safe queue based on linked nodes that orders elements according to FIFO (First-In-First-Out)?
- A
ConcurrentLinkedQueue
- B
LinkedBlockingQueue
- C
PriorityBlockingQueue
- D
ArrayBlockingQueue
There are 10 questions to complete.