HashSet internally uses?

The most used interfaces from the Collection framework are?

The root interface of Java Collection framework hierarchy is -

Which of these is synchronized?

ArrayList implements which of the following?

Which of these allows the storage of many null values?

nextIndex() and previousIndex() are methods of which interface?

Vector extends which of these?

LinkedList implements?

In Iterator, nextElement() method of Enumeration has been changed to:

Enumeration returned by Vector is?

From Java 5 onwards, which one of these is recommended to replace Hashtable?

Which does not allow to store a null value?

Iterator returned by Vector is?

What describes how well an algorithm performs in best, average or worse case scenarios?

An ordered array has a search time complexity of?

Which Map class must be preferred in multi-threading environment to maintain natural order of keys?

TreeMap implements?

Which list class must be preferred in multi-threading environment, considering performance constraint

Which Set class must be preferred in multi-threading environment, considering performance constraint

Which Map class must be preferred in multi-threading environment, considering performance constraint