JAVA-Day4

Which keyword is used to handle exceptions in Java?

• try

• throw

• catch

• All of the above

What is the purpose of the finally block in exception handling?

• It executes only when an exception occurs.

• It executes only if no exception occurs.

• It always executes, regardless of exceptions.

• It throws exceptions to the calling method.

Which keyword is used to throw an exception explicitly in Java?

• throw

• throws

• catch

• try

Which of the following is an ordered collection of elements in Java?

• HashSet

• TreeSet

• LinkedList

• HashMap

Which collection does not allow duplicate elements?

• List

• ArrayList

• HashSet

• LinkedList

Which collection uses a tree structure to store elements in a sorted order?

• TreeSet

• HashSet

• ArrayList

• LinkedList

Which class implements the Map interface using a hash table?

• TreeMap

• HashMap

• LinkedHashMap

• SortedMap

Which of the following allows null keys in Java?

• HashMap

• TreeMap

• HashSet

• Both A and C

What is the time complexity of retrieving an element from a HashMap using its key?

• O(1)

• O(log n)

• O(n)

• O(n^2)

What is the main difference between HashSet and TreeSet?

• HashSet maintains order, TreeSet does not

• TreeSet allows duplicates, HashSet does not

• HashSet is faster, TreeSet maintains a sorted order

• HashSet uses a tree structure, TreeSet uses hashing