Difference Between Enumeration and Iterator

In Iterator, we can read and remove element while traversing element in the collections. Using Enumeration, we can only read element during traversing element in the collections. 2. It can be used with any class of the collection framework.

1. Why enumeration is faster than iterator?
2. Is enumeration fail fast?
3. Which is better iterator or foreach?
4. What is enumeration in Java?
5. Which iterator is faster and uses less memory?
6. What is enumeration definition?
7. What iterator can throw a ConcurrentModificationException?
8. What does a list iterator do?
9. How do I make an ArrayList thread safe?
10. Is iterator faster than for loop C++?
11. Why iterator is used in Java?
12. Does foreach use iterator?

Why enumeration is faster than iterator?

In the example of the micro-benchmark given, the reason the Enumeration is faster than Iterator is because it is tested first. ;) The longer answer is that the HotSpot compiler optimises a whole method when a loop has iterated 10,000 times.

Is enumeration fail fast?

Fail-fast or Fail-safe : Enumeration is fail-safe in nature. ... Iterator is fail-fast in nature. It throws ConcurrentModificationException if a Collection is modified while iterating other than its own remove() method.

Which is better iterator or foreach?

Difference between the two traversals

In for-each loop, we can't modify collection, it will throw a ConcurrentModificationException on the other hand with iterator we can modify collection. Modifying a collection simply means removing an element or changing content of an item stored in the collection.

What is enumeration in Java?

Enumeration means a list of named constant. In Java, enumeration defines a class type. An Enumeration can have constructors, methods and instance variables. It is created using enum keyword. Each enumeration constant is public, static and final by default.

Which iterator is faster and uses less memory?

Enumeration is twice as fast as compared to an Iterator and uses very less memory.

What is enumeration definition?

1 : the act or process of making or stating a list of things one after another the rebel leader's effective enumeration of popular grievances also : the list itself The restaurant creates an astonishing range of preserved products …

What iterator can throw a ConcurrentModificationException?

Fail-Fast iterators immediately throw ConcurrentModificationException if there is structural modification of the collection. Structural modification means adding, removing any element from collection while a thread is iterating over that collection.

What does a list iterator do?

Like Iterator, ListIterator is a Java Iterator, which is used to iterate elements one-by-one from a List implemented object. It is available since Java 1.2. ... Unlike Iterator, It supports both Forward Direction and Backward Direction iterations. It is a Bi-directional Iterator.

How do I make an ArrayList thread safe?

A thread-safe variant of ArrayList in which all mutative operations (e.g. add, set, remove..) are implemented by creating a separate copy of underlying array. It achieves thread-safety by creating a separate copy of List which is a is different way than vector or other collections use to provide thread-safety.

Is iterator faster than for loop C++?

Iterating over a vector using iterators is not faster and is not safer (actually if the vector is possibly resized during the iteration using iterators will put you in big troubles). The idea of having a generic loop that works when you will change later the container type is also mostly nonsense in real cases.

Why iterator is used in Java?

An Iterator is an object that can be used to loop through collections, like ArrayList and HashSet. It is called an "iterator" because "iterating" is the technical term for looping. To use an Iterator, you must import it from the java.

Does foreach use iterator?

Collections can be iterated easily using two approaches. Using for-Each loop − Use a foreach loop and access the array using object. Using Iterator − Use a foreach loop and access the array using object.