Java Collection Set

-Contains no duplicate elements.

-Can contain at most one Null value.

-Elements are not key-value pairs.

-Accessing an element can be almost as fast as performing a similar operation on an array.

Which of these classes provides the specified features?

• LinkedList

• TreeMap

• HashSet

• LinkedHashMap

• HashMap

Which of the following statements are true with respect to sets as objects of Hashset?

• Set is always an ordered group of objects.

• Set allows duplicate objects.

• Set does not allow duplicate objects.

• Set supports iterators.

Which of the following interfaces declares a core method that all collections will have?

• EventListener

• Comparator

• Set

• Collection

Which of the following statements are correct with respect to a Map in Java?

• A map can have iterators for accessing its elements.

• The elements of a map are accessed by the respective keys.

• Maps are the same as a SortedSet.

• None of these.

Which of the following interfaces must contain a unique element?

• List

• Set

• Array

• Collection

Which of the following statements are correct with respect to a List in Java?

• A List is implemented in the "first-in, first-out" (FIFO) order.

• A List is implemented in the "first-in, last-out" (FILO) order.

• Lists support duplicate items.

• None of these.

We need to access elements frequently by using index...

Which one is better solution?

• Set

• List

• Map

We want store data in form Key and Value... Whic one is better solution?

• Set

• List

• Map

We want to create collection of unique elements without duplicates... Which one is better solution?

• Set

• List

• Map

Contains no duplicate elements

Elements are not key-value pairs

Always unique elements

• LinkedList

• TreeMap

• HashSet

• HashMap