Java Collections

Which of the following is a correct difference between ArrayList and Vector?

• ArrayList increases its size by doubling the array size while Vector increases by 50% of the array size.

• ArrayList is synchronized while Vector is not.

• ArrayList is not a legacy class while Vector is the legacy.

• None

When would you choose to use ArrayList over LinkedList in an application?

• ArrayList is preferred when there is more demand for get via index operations.

• ArrayList is preferred when there is growing need of merging or sorting operations.

• ArrayList is preferred when there are frequent insertions or deletions required in the application.

• None

Which of the following is a correct method to convert the array of strings into a list?

• Arrays class toList() method

• Arrays class asList() method

• Arrays class doList() method

Which of the following is a correct difference between List and Set?

• List maintains no order whereas Set maintains ascending order.

• List contain only unique elements whereas Set can contain duplicate elements.

• List can hold duplicate elements while Set includes only unique elements.

What is the correct difference between HashMap and TreeMap?

• HashMap maintains no order but TreeMap maintains ascending order.

• HashMap contains only values whereas TreeMap contains key and values both.

• HashMap can contain duplicate elements whereas TreeMap contains only unique elements.

Which of the following method you need to override for using an object as key in a HashMap?

• hashValue()

• hashCode()

• hashKey()

When would you choose to use LinkedList over ArrayList in an application?

• LinkedList is preferred when application requires to perform merging or sorting operations.

• LinkedList is preferred when applications needs to support insertions or deletions of elements.

• LinkedList is preferred when application requires to perform frequent get or search operations.

Which of the following class doesn’t implement the Set interface?

• HashSet

• Linked HashSet

• Tree Set

• None of the above

Which of the following Collection are synchronized by nature ?

• Vector

• Sorted Set

• HashTable

• HashMap

Can elements of a Set be traversed without using Iterator?

• YES

• NO