Java Using Hashtable Program

Basic Hashtable Operations

package com.java2novice.hashtable;

import java.util.Hashtable;

public class MyHashtableOperations

{

public static void main(String a[])

{

 Hashtable ht = new Hashtable();

 ht.put("first", "First inserted");

        ht.put("second", "Second inserted");

        ht.put("third","Third inserted");

        System.out.println(ht);

        System.out.println("Value of key 'second': "+ht.get("second"));

        System.out.println("Is Hashtable empty? "+ht.isEmpty());

        ht.remove("third");

        System.out.println(ht);

        System.out.println("Size of the Hashtable: "+ht.size());

    }

}

How to iterate through Hashtable

package com.java2novice.hashtable;

import java.util.Hashtable;

import java.util.Set;

public class MyHashtableRead

{

 public static void main(String a[])

{

 Hashtable hm = new Hashtable();

        hm.put("first", "First inserted");

        hm.put("second", "Second inserted");

        hm.put("third","Third inserted");

        System.out.println(hm);

        Set keys = hm.keySet();

        for(String key: keys)

                  {

            System.out.println("Value of "+key+" is: "+hm.get(key));

        }

    }

}

How to copy Map content to another Hashtable

package com.java2novice.hashtable; 

import java.util.HashMap;

import java.util.Hashtable;

public class MyHashtableCopy

{

public static void main(String a[])

{

 Hashtable hm = new Hashtable();

        hm.put("first", "First inserted");

        hm.put("second", "Second inserted");

        hm.put("third","Third inserted");

        System.out.println(hm);

        HashMap subMap = new HashMap();

        subMap.put("s1", "S1 Value");

        subMap.put("s2", "S2 Value");

        hm.putAll(subMap);

        System.out.println(hm);

    }

}

How to search a key in Hashtable

package com.java2novice.hashtable;

import java.util.Hashtable;

public class MyHashtableKeySearch

{

public static void main(String a[])

{

 Hashtable hm = new Hashtable();

        hm.put("first", "First inserted");

        hm.put("second", "Second inserted");

        hm.put("third","Third inserted");

        System.out.println(hm);

        if(hm.containsKey("first"))

        {

            System.out.println("The Hashtable contains key first");

        }

        else

        {

            System.out.println("The Hashtable does not contains key first");

        }

        if(hm.containsKey("fifth"))

        {

            System.out.println("The Hashtable contains key fifth");

        }

         else

       {

            System.out.println("The Hashtable does not contains key fifth");

        }

    }

}

How to search a value in Hashtable

package com.java2novice.hashtable;

import java.util.Hashtable;

public class MyHashtableValueSearch

{

public static void main(String a[])

{

        Hashtable hm = new Hashtable();

        hm.put("first", "First inserted");

        hm.put("second", "Second inserted");

        hm.put("third","Third inserted");

        System.out.println(hm);

        if(hm.containsValue("Second inserted"))

       {

            System.out.println("The Hashtable contains value Second inserted");

        }

        else

      {

            System.out.println("The Hashtable does not contains value Second inserted");

        }

        if(hm.containsValue("first"))

       {

            System.out.println("The Hashtable contains value first");

        }

        else

      {

            System.out.println("The Hashtable does not contains value first");

        }

    }

}