Here is a Java Program to Demonstrate HashMap
Output of Above Java Program
John Doe: 3434.34
Tom Smith: 123.22
Jane Baker: 1378.0
Tod Hall: 99.22
Ralph Smith: -19.08
John Doe's new balance: 4434.34
import java.util.*; class HashMapDemo { public static void main(String args[]) { // Create a hash map HashMap hm = new HashMap(); // Put elements to the map hm.put("John Doe", new Double(3434.34)); hm.put("Tom Smith", new Double(123.22)); hm.put("Jane Baker", new Double(1378.00)); hm.put("Tod Hall", new Double(99.22)); hm.put("Ralph Smith", new Double(-19.08)); // Get a set of the entries Set set = hm.entrySet(); // Get an iterator Iterator i = set.iterator(); // Display elements while(i.hasNext()) { Map.Entry me = (Map.Entry)i.next(); System.out.print(me.getKey() + ": "); System.out.println(me.getValue()); } System.out.println(); // Deposit 1000 into John Doe's account double balance = ((Double)hm.get("John Doe")).doubleValue(); hm.put("John Doe", new Double(balance + 1000)); System.out.println("John Doe's new balance: " + hm.get("John Doe")); } }
Output of Above Java Program
John Doe: 3434.34
Tom Smith: 123.22
Jane Baker: 1378.0
Tod Hall: 99.22
Ralph Smith: -19.08
John Doe's new balance: 4434.34