example code HashMap

package myutil;

//HASHMAP    

import java.io.*;
import java.util.*;
public class HashMapInet
{
         public static void main(String args[])throws IOException
         {
    HashMap hm=new HashMap();
    String name,str;
     Long phno;
    BufferedReader br=new BufferedReader(new InputStreamReader(System.in));
    //MENU
    while(true)
    {
          System.out.println("1.Enter entries into phone book");
          System.out.println("2.Look up in phone book");
      System.out.println("Enter ur choice");
      int n=Integer.parseInt(br.readLine());
      switch(n)
    {
         case 1:
        System.out.println("Enter name");
        name=br.readLine();
        System.out.println("Enter phone no");
        str=br.readLine();
        phno=new Long(str);
        hm.put(name,phno);
        break;
        case 2:
        System.out.println("Enter name");
        name=br.readLine();
        phno=(Long)hm.get(name);
        System.out.println("phone no=" + phno);
        break;
      default:
        return;
    }
               }
        }
}    

output:
1.Enter entries into phone book
2.Look up in phone book
Enter ur choice
1
Enter name
Laxman
Enter phone no
9885988311
1.Enter entries into phone book
2.Look up in phone book
Enter ur choice
2
Enter name
Laxman
phone no=9885988311
1.Enter entries into phone book
2.Look up in phone book
Enter ur choice