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Can Iterator be used for Hashtable?

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Can Iterator be used for Hashtable?

Using Iterator we can display Hashtable key and value separately for each pair of elements.

How an Hashtable can change the Iterator in Java?

priyanka

  1. priyanka. Answered On : Sep 30th, 2005.
  2. Hashtable will change the iterator by using Enumerator interface.Yes,we can iterate a hashmap using the entrySet() method.

How do you go through a Hashtable?

Various ways to iterate through Hashtable – 6 ways

  1. Way 1: Using Enumeration interface in Java 1.0 version.
  2. Way 2: Get keys using keySet() method of Map and iterate using enhanced for loop.
  3. Way 3: Get keys using keySet() method of Map and iterate using Iterator interface.

Is Hashtable a data structure?

In computing, a hash table (hash map) is a data structure that implements an associative array abstract data type, a structure that can map keys to values. A hash table uses a hash function to compute an index, also called a hash code, into an array of buckets or slots, from which the desired value can be found.

What is the difference between HashMap and Hashtable?

HashMap is non-synchronized. It is not thread-safe and can’t be shared between many threads without proper synchronization code whereas Hashtable is synchronized. HashMap allows one null key and multiple null values whereas Hashtable doesn’t allow any null key or value.

Where is Hashtable used in Java?

The Hashtable class implements a hash table, which maps keys to values. Any non-null object can be used as a key or as a value. To successfully store and retrieve objects from a hashtable, the objects used as keys must implement the hashCode method and the equals method.

How to iterate over hashtable values in Java?

How to iterate over Hashtable values? We can get all the values contained in the Hashtable object using the elements method. It returns an Enumeration of all the values of the hash table object. Once we get the enumeration, we can iterate through the values using the hasMoreElements and nextElement methods.

How to use an iterator in Java?

To use an iterator, we must import java.util package. An Iterator interface is used in place of Enumeration in Java Collection. Enumeration is not a universal iterator and is used for legacy classes like Vector, Hashtable only.

What is the use of enumeration keys in hashtable?

5) Enumeration keys (): Returns an enumeration of the keys contained in the hash table. 6) Object put (Object key, Object value): Maps the specified key to the specified value in this hashtable. 7) void rehash (): Increases the size of the hash table and rehashes all of its keys.

What is the difference between HashMap and hashtable in Java?

This class implements a hash table, which maps keys to values. Any non-null object can be used as a key or as a value. Hashtable is similar to HashMap except it is synchronized. There are few more differences between HashMap and Hashtable class, you can read them in detail at: Difference between HashMap and Hashtable.

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