Explore topic-wise MCQs in Java.

This section includes 11 Mcqs, each offering curated multiple-choice questions to sharpen your Java knowledge and support exam preparation. Choose a topic below to get started.

1.

When an array is passed to a method, will the content of the array undergo changes with the actions carried within the function?

A. True
B. False
Answer» B. False
Discussion
2.

What is the worst case complexity of accessing an element in ArrayList?

A. O(n)
B. O(1)
C. O(nlogn)
D. O(2)
Answer» C. O(nlogn)
Discussion
3.

Which of the below is not an implementation of List interface?

A. RoleUnresolvedList
B. Stack
C. AttibuteList
D. SessionList
Answer» E.
Discussion
4.

Which class provides thread safe implementation of List?

A. ArrayList
B. CopyOnWriteArrayList
C. HashList
D. List
Answer» C. HashList
Discussion
5.

What is the difference between length() and size() of ArrayList?

A. length() and size() return the same value
B. length() is not defined in ArrayList
C. size() is not defined in ArrayList
D. length() returns the capacity of ArrayList and size() returns the actual number of elements stored in the list
Answer» E.
Discussion
6.

How to remove duplicates from List?

A. HashSet<String> listToSet = new HashSet<String>(duplicateList);
B. HashSet<String> listToSet = duplicateList.toSet();
C. HashSet<String> listToSet = Collections.convertToSet(duplicateList);
D. HashSet<String> listToSet = duplicateList.getSet();
Answer» B. HashSet<String> listToSet = duplicateList.toSet();
Discussion
7.

How can we remove an object from ArrayList?

A. remove() method
B. using Iterator
C. remove() method and using Iterator
D. delete() method
Answer» D. delete() method
Discussion
8.

WHEN_AN_ARRAY_IS_PASSED_TO_A_METHOD,_WILL_THE_CONTENT_OF_THE_ARRAY_UNDERGO_CHANGES_WITH_THE_ACTIONS_CARRIED_WITHIN_THE_FUNCTION??$

A. True
B. False
Answer» B. False
Discussion
9.

How is Arrays.asList() different than the standard way of initialising List?

A. Both are same
B. Arrays.asList() throws compilation error
C. Arrays.asList() returns a fixed length list and doesn’t allow to add or remove elements
D. We cannot access the list returned using Arrays.asList()
Answer» D. We cannot access the list returned using Arrays.asList()
Discussion
10.

When two threads access the same ArrayList object what is the outcome of the program?

A. Both are able to access the object
B. ConcurrentModificationException is thrown
C. One thread is able to access the object and second thread gets Null Pointer exception
D. One thread is able to access the object and second thread will wait till control is passed to the second one
Answer» C. One thread is able to access the object and second thread gets Null Pointer exception
Discussion
11.

How to sort elements of ArrayList?

A. Collection.sort(listObj);
B. Collections.sort(listObj);
C. listObj.sort();
D. Sorter.sortAsc(listObj);
Answer» C. listObj.sort();
Discussion