Java Interview Questions 3

11: What is the Collection interface?
A: The Collection interface provides support for the implementation of a mathematical bag - an unordered collection of objects that may contain duplicates.

12: What is the Set interface?
A: The Set interface provides methods for accessing the elements of a finite mathematical set. Sets do not allow duplicate elements.

13: What is the typical use of Hashtable?
A: Whenever a program wants to store a key value pair, one can use Hashtable.

14: I am trying to store an object using a key in a Hashtable. And some other object already exists in that location, then what will happen? The existing object will be overwritten? Or the new object will be stored elsewhere?
A: The existing object will be overwritten and thus it will be lost.

15: What is the difference between the size and capacity of a Vector?
A: The size is the number of elements actually stored in the vector, while capacity is the maximum number of elements it can store at a given instance of time.