Core Java - Interview Questions and Answers for 'Collection' | Search Interview Question - javasearch.buggybread.com
Javasearch.buggybread.com

Search Interview Questions


 More than 3000 questions in repository.
 There are more than 900 unanswered questions.
Click here and help us by providing the answer.
 Have a video suggestion.
Click Correct / Improve and please let us know.
Label / Company      Label / Company / Text

   



Interview Questions and Answers - Order By Rating

   
 Q151. Which of the following collections stores its elements in insertion Order ?

a. HashMap
b. TreeMap
c. LinkedHashMap
d. LinkedMap		Core Java
Ans. LinkedHashMap

  Sample Code for LinkedHashMap

 Help us improve. Please let us know the company, where you were asked this question :   

   Like         Discuss         Correct / Improve     linkedhashmap   collections   java   map

 Q152. If we add Enum constants to a sorted collection ( Treemap , TreeSet ), What will be the order in which they will be maintained ?

a. Sorted Collection wont maintain them in any order.
b. Insertion Order
c. Order in which constants are declared.
d. Natural Sorting Order.
Ans. Order in which constants are declared.

 Help us improve. Please let us know the company, where you were asked this question :   

   Like         Discuss         Correct / Improve     enum   collections   sorted collections   treemap   treeset   compareto   comparable   java

 Q153. If we try to add duplicate key to the HashMap, What will happen ?

a. It will throw an exception.
b. It won't add the new Element without any exception.
c. The new element will replace the existing element.
d. Compiler will identify the problem and will throw an error.
Ans. The new element will replace the existing element.

 Help us improve. Please let us know the company, where you were asked this question :   

   Like         Discuss         Correct / Improve     hashmap   map   collections   java

 Q154. In what order the elements of a HashSet are retrieved ?

a. Random Order
b. Insertion Order
c. Natural Sorting Order
d. Inverse Natural Sorting Order
Core Java
Ans. Random Order

 Help us improve. Please let us know the company, where you were asked this question :   

   Like         Discuss         Correct / Improve     collections   set   hashset   java
Try 1 Question(s) Test

 Q155. Which interface does java.util.Hashtable implement ?

a. List
b. Set
c. Collection
d. Map
Core Java
Ans. Map

 Help us improve. Please let us know the company, where you were asked this question :   

   Like         Discuss         Correct / Improve     hashtable   java   collections

 Q156. Which of the following is false ?

a. HashMap came before HashTable.
b. HashMap allows null values whereas Hashtable doesn’t allow null values.
c. HashTable and HashMap allow Key-Value pairs.
d. Hashtable is synchronized whereas HashMap is not.
Ans. HashMap came before HashTable.

 Help us improve. Please let us know the company, where you were asked this question :   

   Like         Discuss         Correct / Improve     map   hashmap   hashtable   collection   java
Try 2 Question(s) Test

 Q157. Which of the collections allows null as the key ?

a. HashTable
b. HashMap
c. TreeMap
d. LinkedHashMap		Core Java
Ans. HashMap

 Help us improve. Please let us know the company, where you were asked this question :   

   Like         Discuss         Correct / Improve     java   collections   map  hashtable     Asked in 2 Companies      basic        frequent

 Q158. Collections.sort can only be performed on ..

a. Set
b. List
c. Map
d. Any Collection implementation		Core Java
Ans. List

 Help us improve. Please let us know the company, where you were asked this question :   

   Like         Discuss         Correct / Improve     collections   java   sorting
Try 2 Question(s) Test

 Q159. Effective Java 6 , TreeMap implements ...

a. Map Interface
b. SortedMap Interface
c. NavigableMap Interface
d. SortedNavigableMap Interface
Ans. SortedMap Interface

 Help us improve. Please let us know the company, where you were asked this question :   

   Like         Discuss         Correct / Improve     java   collections   map

 Q160. Which of the following doesn't extend Collection interface ?

a. Set
b. List
c. Map
d. Queue
Core Java
Ans. Map

 Help us improve. Please let us know the company, where you were asked this question :   

   Like         Discuss         Correct / Improve     java   collections   collection interface

 Q161. Can we add more elements to an array list that has been marked as final ?
Ans. Yes, the array list can hold more elements. Final only puts the restriction that the array list reference cannot hold any other array list.

 Help us improve. Please let us know the company, where you were asked this question :   

   Like         Discuss         Correct / Improve     ebay   collections   arraylist   final keyword

 Q162. Write a method to convert all elements of a set to lower case.Core Java
Ans. http://javasearch.buggybread.com/CodeSnippets/searchCodeSamples.php?keyword=Method+to+convert+all+elements+of+a+collection&category=code

 Help us improve. Please let us know the company, where you were asked this question :   

   Like         Discuss         Correct / Improve     code  coding  string  String.toLowerCase  set  collections

Recently asked in Sophos
 Q163. Write a Method to get a map of words and their count by passing in the stringCore Java
Ans. http://javasearch.buggybread.com/CodeSnippets/searchCodeSamples.php?keyword=Method+to+get+a+map+of+words&category=code

 Help us improve. Please let us know the company, where you were asked this question :   

   Like         Discuss         Correct / Improve     map  collections     Asked in 2 Companies      intermediate

 Q164. Have you ever looked into internal implementation of Java Collections ?
Ans. Yeah, I once looked into implementation of TreeSet and TreeMap just for learning.

 Help us improve. Please let us know the company, where you were asked this question :   

   Like         Discuss         Correct / Improve     collections

 Q165. Write code to sort elements of a set
Ans. http://javasearch.buggybread.com/CodeSnippets/searchCodeSamples.php?&category=code&searchOption&keyword=952

 Help us improve. Please let us know the company, where you were asked this question :   

   Like         Discuss         Correct / Improve     set  collections  sorting  treeset  code  coding

 Q166. What is unmodifiable set / unmodifiable map ? How can we create one ?
Ans. It is an unmodifiable / read only view of the underlying collection. We can use

Collections.unmodifiableSet(Set set)
Collections.unmodifiableMap(Map map)
Collections.unmodifiableCollection(Collection collection)

 Help us improve. Please let us know the company, where you were asked this question :   

   Like         Discuss         Correct / Improve     collections  set  unmodifiable set  map  unmodifiable map  unmodifiablemap  unmodifiableset  Collections.unmodifiableCollection  Collections.unmodifiableMap  Collections.unmodifiableSet

  Q167. What is a Destructor ? Do we have Destructors in Java ?Core Java
Ans. Destructor is used to de-allocate memory allocated by objects.

There are no destructors in Java. Alternatively, Java provides Automatic garbage collection i.e automatically releasing the un-referenced memory.

 Help us improve. Please let us know the company, where you were asked this question :   

   Like         Discuss         Correct / Improve     destructor  garbage collection     Asked in 11 Companies      Basic        frequent
Try 1 Question(s) Test

 Q168. Is Iterator a class ?
Ans. No, iterator is an interface that is used to parse through the elements of a Collection

 Help us improve. Please let us know the company, where you were asked this question :   

   Like         Discuss         Correct / Improve     collections  iterator

 Q169. Collections is a / an ..Core Java
a. interface
b. abstract class
c. final class
d. util class

Ans.d. util class
 Q170. What will be the output of exceuting main method ?

public static void main(String[] args){
      List list = new ArrayList();
      list.add(1);
      list.add(2);
      list.add(3);
      System.out.println(list);
   }		Core Java
a. 1,2,3
b. Order cannot be determined
c. compilation error
d. 3,2,1

Ans.a. 1,2,3
 Q171. What will be the output upon executing main method ?

public static void main(String[] args){
      Set set = new HashSet();
      set.add(1);
      set.add(2);
      set.add(3);
      System.out.println(set);
   }		Core Java
a. 1,2,3
b. Order cannot be determined
c. Compilation error
d. 3,2,1

Ans.b. Order cannot be determined
 Q172. Which of the following methods are used by Java Garbage Collection Mechanism ?Core Java
a. final
b. finally
c. finalize
d. All of the above

Ans.c. finalize
 Q173. Which of the following about Garbage collection is false ?Core Java
a. We can call Garbage collection explicitly
b. Garbage Collection guarantees that the application will not run out of memory
c. finalize method is used by Java for Garbage Collection
d. Garbage Collection Mechanism delete unclaimed objects that are no longer required

Ans.b. Garbage Collection guarantees that the application will not run out of memory
 Q174. Which of the following collections stores its elements in natural sorting order ?Core Java
a. HashMap
b. LinkedHashMap
c. TreeMap
d. EnumMap

Ans.c. TreeMap
 Q175. Which of following stores its elements in natural Sorting Order ?Core Java
a. AbstractSet
b. HashSet
c. LinkedHashSet
d. TreeSet

Ans.d. TreeSet
 Q176. What kind of thread is Garbage collection thread ?Core Java
a. Daemon Thread
b. User Thread
c. System Thread
d. Active Thread

Ans.a. Daemon Thread
 Q177. What will be the output of this code

ArrayList list = new LinkedList();
list.add(3);
list.add(2);
list.add(1);
System.out.println(list);		Core Java
a. 1,2,3
b. 3,2,1
c. Order cannot be determined
d. Compilation Error

Ans.d. Compilation Error
 Q178. Which of following memory segment is cleaned by Garbage Collection Mechanism ?Core Java
a. Stack
b. Heap
c. Code
d. Cache

Ans.b. Heap
 Q179. Which of the following collection classes store their elements as Key Value pairs ?Core Java
a. Set
b. List
c. Map
d. Queue

Ans.c. Map
previous 30   

Help us and Others Improve. Please let us know the questions asked in any of your previous interview.

Any input from you will be highly appreciated and It will unlock the application for 10 more requests.

Company Name:
Questions Asked: