Java.util.Dictionary Class in Java

util.Dictionary is an abstract class, representing a key-value relation and works similiar to a map. Given a key you can store values and when needed can retrieve the value back using its key. Thus, it is a list of key-value pair.
Declaration

public abstract class Dictionary extends Object
Constructors:
Dictionary() Sole constructor.
Methods of util.Dictionary Class :

put(K key, V value) : java.util.Dictionary.put(K key, V value) adds key-value pair to the dictionary
Syntax :
public abstract V put(K key, V value)
Parameters :
-> key
-> value
Return :
key-value pair mapped in the dictionary
elements() : java.util.Dictionary.elements() returns value representation in dictionary
Syntax :
public abstract Enumeration elements()
Parameters :
--------
Return :
value enumeration in dictionary
get(Object key) : java.util.Dictionary.get(Object key) returns the value that is mapped with the argumented key in the dictionary
Syntax :

public abstract V get(Object key)
Parameters :
key - key whose mapped value we want
Return :
value mapped with the argumented key
isEmpty() : java.util.Dictionary.isEmpty() checks whether the dictionary is empty or not.
Syntax :
public abstract boolean isEmpty()
Parameters :
------
Return :
true, if there is no key-value relation in the dictionary; else false
keys() : java.util.Dictionary.keys() returns key representation in dictionary
Syntax :
public abstract Enumeration keys()
Parameters :
--------
Return :
key enumeration in dictionary
remove(Object key) : java.util.Dictionary.remove(Object key) removes the key-value pair mapped with the argumented key.
Syntax :
public abstract V remove(Object key)
Parameters :
key : key to be removed
Return :
value mapped with the key
size() : java.util.Dictionary.size() returns the no. of key-value pairs in the Dictionary
Syntax :
public abstract int size()
Parameters :
-------
Return :
returns the no. of key-value pairs in the Dictionary

// Java Program explaining util.Dictionary class Methods
// put(), elements(), get(), isEmpty(), keys()
// remove(), size()

import java.util.*;
public class New_Class
{
public static void main(String[] args)
{

// Initializing a Dictionary
Dictionary geek = new Hashtable();

// put() method
geek.put("123", "Code");
geek.put("456", "Program");

// elements() method :
for (Enumeration i = geek.elements(); i.hasMoreElements();)
{
System.out.println("Value in Dictionary : " + i.nextElement());
}

// get() method :
System.out.println("nValue at key = 6 : " + geek.get("6"));
System.out.println("Value at key = 456 : " + geek.get("123"));

// isEmpty() method :
System.out.println("nThere is no key-value pair : " + geek.isEmpty() + "n");

// keys() method :
for (Enumeration k = geek.keys(); k.hasMoreElements();)
{
System.out.println("Keys in Dictionary : " + k.nextElement());
}

// remove() method :
System.out.println("nRemove : " + geek.remove("123"));
System.out.println("Check the value of removed key : " + geek.get("123"));

System.out.println("nSize of Dictionary : " + geek.size());

}
}
result:

Value in Dictionary : Code
Value in Dictionary : Program

Value at key = 6 : null
Value at key = 456 : Code

There is no key-value pair : false

Keys in Dictionary : 123
Keys in Dictionary : 456

Remove : Code
Check the value of removed key : null

Size of Dictionary : 1