1. Iterator Declaration

Iterator Vs. Collection

• 
  Iterator can only move to next() element or remove() an element. 
  However Collection can add(), iterate, remove() or clear() the elements of the collection. 
  
• 
  Iterator provides a better speed than Collections, as the Iterator interface has limited number of operations. 
  
• 
  java.sql.SQLException extends Iterable. Hence it allows the caller to safely iterate over causes of SQLException. 
  Using a collection, in this case, would be expensive because, in a chain of n exceptions, use of a collection in the SQLException interface would potentially require the construction of O(n^2) elements. 
  However, use of Iterable provides O(n) access to the exception chain. 
  
  

Last Updated : 01 Mar, 2023
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