Which of the following is true?
A) The retrieve()method of an iterator can only be called after isEmpty()has returned false
B) The remove(.method of an iterator can only be called after next(.has been called
C) Any iterator can move forward as well as backwards through a collection
D) Once an iterator has reached the end of the collection,calling any of its methods will throw a NoSuchElement exception

Question

Quizplus · Accepted Answer

According to the Java documentation, the remove() method of an iterator can only be called after a call to next(), and it will remove the last element returned by the iterator. Therefore, choice B is the only true statement. 
A is not true because sometimes the collection can be non-empty, but the iterator may have already reached the end of the collection (for example, if the iterator is already pointing to the last element of the collection). 
C is not true because not all iterators support bidirectional iteration. Some collections, such as lists, support bidirectional iteration, but others, such as sets, do not. 
D is not true because calling the hasNext() method of an iterator after it has already reached the end of the collection will return false (and not throw a NoSuchElement exception). However, calling other methods such as next() or remove() after reaching the end of the collection will throw a NoSuchElementException.

Which of the Following Is True