Olete.in – MCQs, Mock Tests & Government Job Prep | Apache Commons Apache Common Collections MCQ

Which Map is synchronized?

1. Hashtable
2. ConcurrentSkipListMap
3. ConcurrentHashMap
4. All of these

✅ Correct Answer: 4

Which of these is not an interface in the Collections Framework?

1. Collection
2. group
3. Set
4. List

✅ Correct Answer: 2

Which is best suited to a multi-threaded environment?

1. WeakHashMap
2. Hashtable
3. HashMap
4. ConcurrentHashMap

✅ Correct Answer: 4

concurrentSkipListMap allows

1. one null key
2. many null value
3. all
4. None

✅ Correct Answer: 4

The accuracy and efficiency of a HashMap can be guaranteed with

1. override equals method
2. Override hashCode method
3. None of these
4. All of these

✅ Correct Answer: 4

Which allows the removal of elements from a collection?

1. Enumeration
2. Iterator
3. Both
4. None

✅ Correct Answer: 2

The Comparable interface contains which called?

1. toCompare
2. compare
3. compareTo
4. compareWith

✅ Correct Answer: 3

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

1. Vector
2. ArrayList
3. LinkedList
4. All of these

✅ Correct Answer: 3

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

1. String
2. Integer
3. Double
4. Any of these

✅ Correct Answer: 4

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

1. Fail-fast
2. Fail-safe
3. none
4. All of the above

✅ Correct Answer: 4

Spark is developed in which language R

1. Java
2. Scala
3. Python
4. R

✅ Correct Answer: 2

In Spark Streaming the data can be from what all sources? All of the above

1. Kafka
2. Flume
3. Kinesis
4. All of the above

✅ Correct Answer: 4