🧪 Apache Commons MCQ Quiz Hub

1. Which Map is synchronized?
Hashtable
ConcurrentSkipListMap
ConcurrentHashMap
All of these

2. Which of these is not an interface in the Collections Framework?
Collection
group
Set
List

3. Which is best suited to a multi-threaded environment?
WeakHashMap
Hashtable
HashMap
ConcurrentHashMap

4. concurrentSkipListMap allows
one null key
many null value
all
None

5. The accuracy and efficiency of a HashMap can be guaranteed with
override equals method
Override hashCode method
None of these
All of these

6. Which allows the removal of elements from a collection?
Enumeration
Iterator
Both
None

7. The Comparable interface contains which called?
toCompare
compare
compareTo
compareWith

8. Which provides better performance for the insertion and removal from the middle of the list?
Vector
ArrayList
LinkedList
All of these

9. Which of these class should be preferred to be used as a key in a HashMap?
String
Integer
Double
Any of these

10. Iterator returned by ConcurrentHashMap on key, value and entry is?
Fail-fast
Fail-safe
none
All of the above

11. Spark is developed in which language R
Java
Scala
Python
R

12. In Spark Streaming the data can be from what all sources? All of the above
Kafka
Flume
Kinesis
All of the above