You are here:

Hashmap Java Example?

This Comment will be submitted for moderation and will not be accessible to other users until it has been approved.

can someone provide me with some nice and quick example of hashmap in java?

1 year 43 weeks ago Tags:

Map is an object that stores key/volume pairs. Given a key, you can find its value. Keys must be unique, but values may be duplicated. The HashMap class provides the primary implementation of the map interface. The HashMap class uses a hash table to implementation of the map interface. This allows the execution time of basic operations, such as get() and put() to be constant.

This code shows the use of HaspMap. In this program HashMap maps the names to account balances.

import java.util.*;
 
public class HashMapDemo {
 
  public static void main(String[] args) {
 
    HashMap hm = new HashMap();
    hm.put("Rohit", new Double(3434.34));
    hm.put("Mohit", new Double(123.22));
    hm.put("Ashish", new Double(1200.34));
    hm.put("Khariwal", new Double(99.34));
    hm.put("Pankaj", new Double(-19.34));
    Set set = hm.entrySet();
 
    Iterator i = set.iterator();
 
    while(i.hasNext()){
      Map.Entry me = (Map.Entry)i.next();
      System.out.println(me.getKey() + " : " + me.getValue() );
    }
 
    //deposit into Rohit's Account
    double balance = ((Double)hm.get("Rohit")).doubleValue();
    hm.put("Rohit", new Double(balance + 1000));
 
    System.out.println("Rohit new balance : " + hm.get("Rohit"));
 
  }
}

Output Screen:

Rohit : 3434.34
Ashish : 1200.34
Pankaj : -19.34
Mohit : 123.22
Khariwal : 99.34
Rohit new balance : 4434.34

Tony

Created by Anonymous

reply
Reset vote
10 points

while using hashmap its important to consider rehashing. because when hashmap reached its threshold specified by its load-factor and capacity it creates another Map and rehash all bucket location which could potentially slowdown insertion in map , see How HashMap works in Java for more details

Created by Anonymous

reply
Reset vote
2 points

Objective C Tutorial

Linux Tutorial

Java Tutorial

JavaScript Tutorial

Ruby Tutorial

HTML Tutorial

HTML5 Tutorial

C++ Tutorial

Drupal Tutorial

Perl Tutorial

PHP Tutorial

CSS Tutorial

Relevant Tutorials

Hashmap Java Example?

Post Comment