Data Structures(Hashtable) in Java

Example: Hashtable
The following program illustrates several of the methods supported by this data structure:

import java.util.*;
public class HashTableDemo {
public static void main(String args[]) {
Hashtable balance = new Hashtable();
Enumeration names;
String str;
double bal;
balance.put("Zara", new Double(3434.34));
balance.put("Mahnaz", new Double(123.22));
balance.put("Ayan", new Double(1378.00));
balance.put("Daisy", new Double(99.22));
balance.put("Qadir", new Double(-19.08));
// Show all balances in hash table.
names = balance.keys();
while(names.hasMoreElements()) {
str = (String) names.nextElement();
System.out.println(str + ": " +
balance.get(str));
}
System.out.println();
bal = ((Double)balance.get("Zara")).doubleValue();
balance.put("Zara", new Double(bal+1000));
System.out.println("Zara's new balance: " +
balance.get("Zara"));
}
}