Skip to main content

Object Oriented Programming (OOP)

Object

Object is an entity that has state and behavior

Class

Collection of objects is known as class.

There are four main types of OOP concepts

  • Inheritance
    • Object acquire all the properties and behavior of parent object
    • Improve code re-usability
  • Polymorphism
    • One task is performed by different ways
    • Use method overload and override
  • Abstraction
    • Hiding internal details and showing functionality
    • Use abstract class and interfaces
  • Encapsulation
    • Binding code and data into a single unit

Comments

Popular posts from this blog

Model-View-Controller (MVC)

MVC(Model-View-Controller) is a software design pattern.It divided your applications into three components Model: Contain business rules and application Data View: Presentation layer (user interface) Controller: Handles the communication between view and model  Objectives of MVC Promote code usability Implement separation of concerns  Separate user interface and software logic Web Frameworks That Use MVC There are several web frameworks that use MVC design pattern.  Ruby On Rails (Ruby) Angular (JS) Django (Python) Express (JS) Flask (Python) Codeigniter (PHP) Simple UseCase for MVC In this use case scenario, Browser sends information that needs to create Employee Object, and Controller save that information in Model and Update the Employee View. Following Image shows the class diagram for above Scenario. Implementation:  https://github.com/kaosadi17/MVC

Hibernate

Hibernate is an ORM (Object Relational Mapping) tool which is primarily used in the data layer. Object Relational Mappings Problems There are several problems can occur when you are trying to save objects in the database from the scratch without using Hibernate. Mapping member variables to columns Mapping relationships Handling data types Managing changes to an object Set Up the Development Environment  Following steps are briefly pointed out how to set up Hibernate on your local machine. Download the hibernate jar files Create a project in Eclipse Right click on the project name and go to properties Navigate to libraries tab Add library and import jar files (lib-> JPA/required) Add Postgres JDBC driver as jar file Configurations After you set up the Hibernate you have to create hiberante.cfg.xml file and do some configurations like setup database details, entity class, etc. Dialect: Define what kind of language should use to talk...

Core Java Concepts

Java Applications  There are mainly four types of Java applications. Standalone Web  Enterprise  Mobile Java Features  There are several features in Java, but in here listed some important ones Platform independent Object oriented Multi threaded Distributed Robust (automatic garbage collection, exception handling, type checking) Java Security  Java has 3 built-in security components; Classloader: Separate class files packages from imported packages. BytecodeVerifier: check the illegal access to objects Security Manager: check what resources can access the object. C++ vs Java Methods Static - No need to create an object to invoke the static method. Constructor - use to initialize objects Constructor name must same as the class name Constructor has no return type There are two types of constructors Default - no parameter Parameterized If there is no constructor defined in the class, compiler aut...