Polymorphism in Java

What is polymorphism in Java? Polymorphism in Java is the principle by which an object can have multiple forms but each form conforms to a contract. Polymorphism can be thought of as a direct consequence of abstraction. In the earlier section, we say how abstraction separates method definition from its implementation. When we have two … Read more

Create AWS EC2 instance using CLI

In the previous tutorial we saw how to create AWS EC2 instance using the console. In this tutorial, we will learn how to create AWS EC2 instance using the CLI (Command Line Interface). create AWS EC2 instance using CLI What is Amazon CLI Amazon CLI stands for Amazon Client Line Interface. It is a command … Read more

Access Modifiers in Java

What are the Access Modifiers in Java? Access Modifiers in Java control access to classes, methods, and variables. There are four basic access modifiers and they are public, protected, private and no modifier (Default). We will use the word default instead of no modifier for the rest of the tutorial. Here’s a summary of the … Read more

Using Imports in Java and importing packages

What does the import statement in java do? In an earlier tutorial we saw an introduction to java. In this tutorial, we will look at using imports in java. To state it plainly – import statements allows us to use the name of the class in our code instead of its fully qualified name. What … Read more

PhoneGap App Error Message : Unable to download archive

If you get an error on PhoneGap App that says “Unable to download archive from the server” when using PhoneGap on Windows then try this : Download the latest build zip from https://github.com/phonegap/phonegap-app-desktop/releases and replace the contents of C:\Program Files (x86)\Adobe\PhoneGap\PhoneGap Desktop with the contents from this zip Open up Windows firewall -> Click on … Read more

Bridge Design Pattern

What is Bridge design pattern? The Bridge Design Pattern is used when there is one set of classes (abstraction) that define features and another set of classes (implementation) that provide the implementation for that features. You then ‘add’ a bridge by injecting the base of the implementation hierarchy to the base of the abstraction hierarchy. … Read more

Amazon Elastic Cloud Compute (EC2) – Introduction

This tutorial gives an introduction to Amazon EC2 Instance. Introduction to Amazon EC2 instance (Elastic Cloud Compute) What is Amazon Elastic Cloud Compute (EC2) Amazon Elastic Cloud Compute (EC2) is a service from Amazon that allows you to create machines in the cloud on-demand. Traditionally, the procedure for obtaining a new machine is probably not … Read more