Java Technologies

Java:

Java is a Class-based, Object-oriented programming language developed by Sun Microsystems in 1995 (acquired by Oracle)

Java n it's technologies:

Java is a programming language that produces software for multiple platforms. When a programmer writes a Java application, the compiled code (known as bytecode) runs on most operating systems (OS), including Windows, Linux and Mac OS. Java derives much of its syntax from the C and C++ programming languages.

1.       (J2SE)  Java 2 Platform, Standard Edition

2.       (J2EE) Java 2 Platform, Enterprise Edition

3.       (J2ME) Java 2 Platform, Micro Edition

Java SE/J2SE / Core Java /(Java Platform, Standard Edition):

Also known as Core Java, this is the most basic and standard version of Java. It’s the purest form of Java, a Java SE (formerly J2SE) is the basic Java environment. basic foundation for all other editions. J2SE is mainly used to create applications for Desktop environment.

Java SE – Standard Edition (a plain Java version) OR Core Java, Java platform editions, is used to develop Java SE – portable desktop apps. Java Platform, Standard Edition (Java SE) is a computing platform for development and deployment of portable code for desktop and server environments

Java SE stands for Java standard edition and is normally for developing desktop applications, forms the core/base API.

It consist all the basics of Java the language, variables, primitive data types, Arrays, Streams, Strings

(JDK, JRE, JVM, JIT,  Java bean,  AWT/ Swing, Java Database Connectivity(JDBC), APi, Frameworks)

JDK JRE JVM and JIT:

·         JDK (Java Development Kit)

·         JRE (Java Runtime Environment)

·         JVM (Java Virtual Machine)

·         JIT (Just-In-Time) Compiler

Java Development Kit (JDK) contains JRE along with various development tools like Java libraries, Java source compilers, Java debuggers, bundling and deployment tools. Just In Time compiler (JIT) is runs after the program has started executing, on the fly.

Java Bean - JavaBeans are classes that encapsulate many objects into a single object (the bean). It is a java class in java.

AWT/Swing:

AWT (Abstract Window Toolkit): AWT is an API to develop GUI or window-based applications in java. It is to create graphical user interface ( GUI ) objects, such as buttons, scroll bars, and windows. AWT is part of the Java Foundation Classes ( JFC ) from Sun Microsystems.

Swing

·         Swing is a set of program components for Java programmers that provide the ability to create graphical user interface ( GUI ) components, such as buttons and scroll bars, that are independent of the windowing system for specific operating system. Swing components are used with the Java Foundation Classes ( JFC ).

·         Swing Framework contains a set of classes that provides more powerful and flexible GUI components than those of AWT. Swing provides the look and feel of modern Java GUI. Swing library is an official Java GUI tool kit released by Sun Microsystems. It is used to create graphical user interface with Java.

JDBC (Java Database Connectivity): JDBC is a Java API to connect and execute the query with the database. It is a part of JavaSE (Java Standard Edition). JDBC API uses JDBC drivers to connect with the database.

API (Application program interface):

·         An API is a software intermediary that allows two applications to talk to each other. In other words, an API is the messenger that delivers your request to the provider that you're requesting it from and then delivers the response back to you.It is the way for an application to interact with certain system/application/library/etc.

·         It is a mechanism that allows the interaction between two applications using a set of rules. The interaction between applications refers to when one application wants to access data that another application holds or send the data to the said application. It can also be when one application is requesting services from another application.

·         API provides interactions between one software and another, but not users, For example, by including or integrating a Javascript Google Maps API in the code, developers can add the feature of interactive Google Maps to an application or a web page. Another example is a YouTube Data API. Using this API, developers can include YouTube functionality to the site to retrieve and manipulate resources like videos, playlists, and channels.

API models – Public & Private APIs

API stands for Application Programming Interface, i.e. API is the way for an application to interact with certain system/application/library/etc.

Web APIs:

Among several API types, web APIs are widely used to integrate software or a service in a website or app through World Wide Web. That means through HTTP protocol the exchange of data or information occurs between desktop, mobile and web applications. Depending on the data transfer formats used in request-response messaging, web APIs are classified as SOAP (Simple Object Access Protocol), RPC (Remote Procedure Call), and REST (Representational State Transfer). These are the different protocols through which exchange of information takes place over web. The most common data formats used to define the response / request messages are XML, JSON, HTML or binary files for documents, videos and images.

The web APIs are further divided into client and server side based on how they extend their functionality in web browser. Client side APIs are broadly used for manipulating different aspects of browser whereas server side APIs are meant for executing functionality on a server before the data is sent to browser. When a request is made to an API, the result will be in the form of response invoking an action. But there are some special server side APIs called webhooks that act as user-defined HTTP callbacks to invoke a behaviour or event. By configuring an event in one website, an action can be automatically invoked in the other. That means whenever the condition is met in the source site, webhooks acknowledge the event, and triggers the action on the url specified in the form of HTTP request. Today, webhooks are widely used for passing the information or triggering specific events between applications and servers.

APIs VS Web Services

·         A web service and an API are two very similar concepts, so it can be difficult to understand the similarities and differences.

·         A web service is a system or software that uses an address, i.e., URL on the World Wide Web, to provide access to its services. A Web service is a way for two machines to communicate with each other over a network.

Web service APIs

Apart from the main web APIs, there are also web service APIs:

1.       SOAP

2.       XML-RPC

3.       JSON-RPC

4.       REST

The following are the most common types of web service APIs:

SOAP (Simple Object Access Protocol): This is a protocol that uses XML as a format to transfer data. Its main function is to define the structure of the messages and method of communication. It also uses WSDL, or Web Services Definition Language, in a machine-readable document to publish a definition of its interface.

XML-RPC: This is a protocol that uses a specific XML format to transfer data compared to SOAP that uses a proprietary XML format. It is also older than SOAP. XML-RPC uses minimum bandwidth and is much simpler than SOAP.

JSON-RPC: This protocol is similar to XML-RPC but instead of using XML format to transfer data it uses JSON.

REST (Representational State Transfer): REST is not a protocol like the other web services, instead, it is a set of architectural principles. The REST service needs to have certain characteristics, including simple interfaces, which are resources identified easily within the request and manipulation of resources using the interface.

A RESTful API is an application program interface (API) that uses HTTP requests to GET, PUT, POST and DELETE data. ... REST technology is generally preferred to the more robust Simple Object Access Protocol (SOAP) technology because REST leverages less bandwidth, making it more suitable for internet usage.

A REST API defines a set of functions which developers can perform requests and receive responses via HTTP protocol such as GET and POST. ... The World Wide Web (WWW) is an example of a distributed system that uses REST protocol architecture to provide a hypermedia driven interface for websites.

REST stands for REpresentational State Transfer. REST is web standards based architecture and uses HTTP Protocol.

REST stands for REpresentational State Transfer. REST is used to build web services that are lightweight, maintainable, and scalable in nature. More and more applications are moving to the Restful architecture.

REST VS RESTful

·         REST stands for Representational State Transfer. ... REST is an architecture all about client-server communication. RESTful web services are web services which are REST based. With RESTful services you an do anything you already do with normal web services.

·         A RESTful API -- also referred to as a RESTful web service -- is based on representational state transfer (REST) technology, an architectural style and approach to communications often used in web services development.

JSON (JavaScript Object Notation) is a lightweight data-interchange format. It is easy for humans to read and write.

Differences between SOAP and REST

SOAP                                                                                                          REST

It has strict rules and advanced security to follow.             There are loose guidelines to follow allowing developers to

 make recommendations easily

It is driven by Function                                                                  It is driven by Data

It requires more Bandwidth                                                         It requires minimum Bandwidth

Differences between JSON and XML

JSON                                                                                                                         XML

Supports only text and numbers.                              Supports various types of data for example text, numbers, images, graphs, charts etc.

Focuses mainly on Data                                                Focuses mainly on Document.

It has low security                                                            It has more security

·         XML [eXtensible Markup Language] is a standardized format for storing and sending data. Similar to HTML, XML stores data by wrapping it in descriptive tags.

·         JSON [JavaScript Object Notation] is similar to XML in that it also stores and enables you to send data in a standardized format. JSON just uses a different, object-based, methodology for systematically storing data.

·         HTTP [HyperText Transfer Protocol] is the foundation of transferring data and communications on the internet.

·         SOAP [Simple Object Access Protocol] is a messaging protocol used for exchanging structured information[XML data] over a network.

·         REST [REpresentational State Transfer] is a standardized architectural style that can be used when creating a web API.

·         Web applications (Web app) are computer programs that are accessed over the internet through a computer’s web browser.

J2EE - Enterprise edition/Java EE (Java Enterprise Edition):

Java EE (formerly J2EE) is the enterprise edition of Java is used to develop enterprise apps, Java EE is an extension for Java SE. J2EE is just a part of Java with a powerful set of libraries, Java EE stands for Java enterprise edition for applications which run on servers, for example web sites.

Beans.

1.       Servlets and JSPs

2.       Framework: Struts Framework , Hibernate Framework , Spring Framework

3.       Working with IDE: Eclipse IDE, Netbeans IDE, Myeclipse IDE,

4.       Servers: Apache Tomcat, Glassfish Server, JBoss Server , Weblogic Server

5.       Web Technology: HTML 5, CSS, Javascript, JQuery, AJAX

6.       EJB3, JNDI , JMS, JPA, EJBQL , MVC, JAR

7.       Design Pattern : Singleton,DAO,DTO,MVC,Front Controller,Factory Method

8.       JUnit, Types of Testing, Maven, Struts2

9.       AOP, ORM, JPA, SpEL, JAXB

What does J2EE comprise?/J2EE components

J2EE is comprised of many APIs that can be used to build enterprise applications. the full list of technologies that make up J2EE is as follows:

1.       Java Servlets

2.       JavaServer Pages (JSP)

3.       Enterprise JavaBeans (EJB)

4.       Java Message Service (JMS)

5.       Java Naming and Directory Interface (JNDI)

6.       Java Database Connectivity (JDBC)

7.       JavaMail

8.       Java Transaction Service (JTS)

9.       Java Transaction API (JTA)

10.   J2EE Connector Architecture (J2EE-CA, or JCA)

Applet:

An Applet is a client side java program that runs within a Web browser on the client machine. On the other hand, a servlet is a server side component that runs on the web Page on server. An applet can use the user interface classes, while a servlet does not have a user interface.

Servlets:

Servlets are the Java programs that runs on the Java-enabled web server or application server. They are used to handle the request obtained from the web server, process the request, produce the response, then send response back to the web server. Properties of Servlets : Servlets work on the server-side. Servlet is a java code.

JSP (JavaServer Pages):

JSP is a server side technology that does all the processing at server. It is used for creating dynamic  web applications, using java as programming.  JavaServer Pages (JSP) is a collection of technologies that helps software developers to create dynamically generated web pages based on HTML, XML, SOAP, or other document types. JSP is similar to

PHP and ASP, but it uses the Java programming language.  JSP is a html based code. Servlet is faster than JSP.

Framework: Framework, is a platform for developing software applications, Frameworks are large bodies of pre-written code to which you add your own code in order to solve a problem. You make use of a framework by calling its methods, inheritance, and supplying callbacks, listeners, or other implementations of the patterns. Top Java frameworks used are:

1.       Spring

2.       Hibernate

3.       Struts

4.       Google web toolkit [GWT]

5.       JavaServer Faces [JSF]

6.       Grails

7.       Vaadin

8.       Blade

9.       Dropwizard

10.   Play

Backend Frameworks:

·         Express

·         Django

·         Rails is a Model-View-Controller framework that uses Ruby

·         Laravel is a Model-View-Controller framework that uses PHP,

·         Spring is a Model-View-Controller framework that uses Java,

Frontend Javascript Frameworks

·         Angular

·         React - React is not a framework, it’s a frontend library, but many developers consider it a framework

·         Vue

·         Ember

·         Backbone

·         AngularJS vs ReactJS vs NodeJS

Micro Services frameworks-

Spring Boot, Spark, Swagger, dropwizard, play framework, Jersey, restlet, restx

Java Script Frameworks- 

AngularJS, ReactJS, NodeJS, VueJS, Polymer, Ember.JS, Backbone.js, Metor, Mithril, Aurelia

Microservices are a form of service-oriented architecture style  wherein applications are built as a collection of different smaller services rather than one whole app.

Microservices/Spring Boot

Microservices architecture is a term used to describe the practice of breaking up an application into a series of smaller, more specialised parts, each of which communicate with one another across common interfaces such as APIs and REST interfaces like HTTP.

What is difference between Web services and Microservices?

·         Microservices are small, autonomous services that work together, while web services are any service that is available over the internet and is built using standard internet technologies. Microservices are a set of small self-sustained small services or applications designed to solve problems for systems that are big.

·         Microservices are a form of service-oriented architecture style (one of the most important skills for Java developers) wherein applications are built as a collection of different smaller services rather than one whole app.

Spring is used to develop application from desktop to Web. Hibernate is used to access data layer and Struts is used for Web frameworks.

Spring Boot is an open source Java-based framework used to create a micro Service.

Spring VS Springboot: Spring Boot. While the Spring framework focuses on providing flexibility to you, Spring Boot aims to shorten the code length and provide you with the easiest way to develop a web application. With annotation configuration and default codes, Spring Boot shortens the time involved in developing an application

IDE (integrated development environment):

An integrated development environment is a software application that provides comprehensive facilities to computer programmers for software development. An IDE normally consists of at least a source code editor, build automation tools and a debugger.

Top free IDE for Java Coding, Development & Programming:

1.       NetBeans

2.       Eclipse

3.       IntelliJ IDEA

4.       Android Studio

5.       Enide Studio 2014

6.       BlueJ

7.       jEdit

8.       jGRASP

9.       JSource

10.   JDeveloper

11.   DrJava

JS (JavaScript), JQuery, Ajax:

JavaScript is an interpreted computer programming language that makes websites more interactive by using web pages as a significant element.

JQuery: JQuery is a library of JavaScript Functions.JQueryacts as the framework of JavaScript.

jQuery is a lightweight, "write less, do more", JavaScript library. The purpose of jQuery is to make it much easier to use JavaScript on your website. jQuery takes a lot of common tasks that require many lines of JavaScript code to accomplish, and wraps them into methods that you can call with a single line of code.

Ajax (Asynchronous JavaScript and XML):

jQuery - Ajax. AJAX is an acronym standing for Asynchronous JavaScript and XML and this technology helps us to load data from the server without a browser page refresh. If you are new with AJAX.

JavaScript is client-side, i.e., in the browser scripting language, whereas jQuery is a library (or framework) built with JavaScript. Meanwhile, AJAX is a method to immediately update parts of the UI without reloading the web pages.

EJB (Enterprise JavaBeans):

EJB is the server-side and platform-independent Java application programming interface (API) for Java Platform, Enterprise Edition (Java EE). EJB is used to simplify the development of large distributed applications.

Enterprise Java Beans

EJB stands for Enterprise Java Beans. EJB is an essential part of a J2EE platform. J2EE platform has component based architecture to provide multi-tiered, distributed and highly transactional features to enterprise level applications.

JNDI (Java Naming and Directory Interface): JNDI is a Java API for a directory service that allows Java software clients to discover and look up data and resources (in the form of Java objects) via a name. Like all Java APIs that interface with host systems, JNDI is independent of the underlying implementation.

JNDI (Java Naming and Directory Interface) enables Java platform-based applications to access multiple naming and directory services.

JMS (The Java Message Service): JMS API is a Java message-oriented middleware API for sending messages between two or more clients. It is an implementation to handle the producer–consumer problem. Java Message Service (JMS) is an application program interface (API) from Sun Microsystems that supports the formal communication known as messaging between computers in a network. JMS API is used to create, send, receive and read messages or exchange messages between different systems.

JavaMail is a Java API used to send and receive email via SMTP, POP3 and IMAP. JavaMail is built into the Java EE platform, but also provides an optional package for use in Java SE.

JPA (The Java Persistence API): JPA is a Java specification for accessing, persisting, and managing data between Java objects / classes and a relational database. JPA was defined as part of the EJB 3.0 specification as a replacement for the EJB 2 CMP Entity Beans specification. JPA also requires a database to persist to.

EJB QL or EJB-QL is a portable database query language for Enterprise Java Beans. It was used in Java EE applications. Compared to SQL, however, it is less complex but less powerful as well.

JAR (Java ARchive): A JAR is a package file format typically used to aggregate many Java class files and associated metadata and resources into one file for distribution. It is used to store classes of java created by the user in order to help the runnable and inference concepts embedded within the language.

A JAR (Java ARchive) is a way of packaging together all of the resources associated with a program (class files, images, sounds, etc.). Putting your program in a JAR allows it to be distributed as a single executable file, saving space and simplifying the download process.

The Java Transaction Service (JTS) is a specification for building a transaction manager that maps onto the Object Management Group (OMG) Object Transaction Service (OTS) used in the Common Object Request Broker Architecture (CORBA) architecture. The Java Transaction API, one of the Java Enterprise Edition APIs, enables distributed transactions to be done across multiple X/Open XA resources in a Java environment. JTA is a specification developed under the Java Community Process as JSR 907.

JCA (Java EE Connector Architecture): Java EE Connector Architecture (JCA) is a Java-based tool for connecting application servers and enterprise information systems (EIS) as part of enterprise application integration (EAI) solutions. While JDBC is specifically used to connect Java EE applications to databases, JCA is a more generic architecture for connection to legacy systems. JCA was developed under the Java Community Process as JSR 16 (JCA 1.0), JSR 112 (JCA 1.5) and JSR 322 (JCA 1.6).

Mocha or Jasmine - JavaScript Testing Framework

Design Patterns in Java:

Design patterns represent the best practices used by experienced object-oriented software developers. Design patterns are solutions to general problems that software developers faced during software development.In the context of Java, design patterns are divided into three categories – creational, structural, and behavioral patterns.

MVC Design Pattern, DAO (Data Access Object Pattern),Data transfer object (DTO), formerly known as value objects or VO, is a design pattern used to transfer data between software application subsystems.

Singleton design pattern, Front controller design pattern, Factory method is a creational design pattern.

Design architectures: MVC, MVVM, MVVM-C, MVC-C, MVP

MVC (Model-View-Controller): MVC is an application design model comprised of three interconnected parts. The MVC model or "pattern", View & Controller is commonly used for developing modern user interfaces. It is provides the fundamental pieces for designing a programs for desktop or mobile, as well as web applications. The Model-View-Controller (MVC) is an architectural pattern that separates an application into three main logical components: the model, the view, and the controller. MVC is one of the most frequently used industry-standard web development framework to create scalable and extensible projects.

AOP (Aspect oriented programming): AOP framework is one of the key components of Spring Framework .

ORM (Object-relational mapper): ORM is a code library that automates the transfer of data stored in relational databases tables into objects that are more commonly used in application code. Hibernate is an ORM framework.

SpEL - Spring Expression Language

JAXB: Java Architecture for XML Binding is a software framework that allows Java developers to map Java classes to XML representations.

Apache Struts 2 is an open-source web application framework for developing Java EE web applications. It uses and extends the Java Servlet API to encourage developers to adopt a model–view–controller architecture.

Groovy:

Apache Groovy is a Java-syntax-compatible object-oriented programming language for the Java platform. It is both a static and dynamic language with features similar to those of Python, Ruby, and Smalltalk. Java is strongly and statically typed language whereas Groovy is dynamically and optionally typed language . The best things about groovy is that Since it extends JDK , it accepts the java code.

WSDL (Web Services Description Language):

·         WSDL is an XML format for describing network services as a set of endpoints operating on messages containing either document-oriented or procedure-oriented information.

·         The Web Services Description Language is an XML-based interface description language that is used for describing the functionality offered by a web service.

Scripting language:

A script or scripting language is a computer language with a series of commands within a file that is capable of being executed without being compiled. Good examples of server-side scripting languages include Perl, PHP, and Python. The best example of a client side scripting language is JavaScript.

Python is considered a scripting language because of a historical blur between scripting languages and general purpose programming languages. In fact, Python is not a scripting language, but a general purpose programming language that also works a nicely scripting language.

What is difference between programming language and scripting language?

Basically, all scripting languages are programming languages. The theoretical difference between the two is that scripting languages do not require the compilation step and are rather interpreted. Generally, compiled programs run faster than interpreted programs because they are first converted native machine code.

J2ME - Micro edition

J2ME is used to develop mobile apps, Java ME stands for Java micro edition for applications which run on resource constrained devices (small scale devices) like cell phones, for example games.

Web Technologies – Java

From a developer perspective, the main technologies are EJB, JSP, Java Servlets, JDBC and JMS, although JNDI is used for locating EJBs and other enterprise resources. For the moment, let's take a quick look at some of these technologies before moving on to see how to get started with J2EE.

Java, EJB, RMI, Swing, CORBA, Serve lets, JSP, JDBC, Core Java, Struts framework, Web sphere, Web logic, HTML, XML, Java script, J2SE, J2EE, J2ME, DOT NET, framework, LDAP, Internet Security, JVM, Pjava, MIPS, Tibco, Board Design, Ematrix, XSL, XSLT, Java Persistence API (JPA), Object Relational Mapping (ORM frame work), SPRING, Hibernate, Struts

Java Fullstack is combination of Frontend and backend

JAVA (frontend) UI: JavaScript, HTML, CSS, DHTML, REST API, Angular, Jquery, React js, Bootstrap, Node js,

JAVA (backend): J2ee, JSF, JSP, Webserices (Rest, SOAP UI), Struts, Spring, hibernate, servlets

What is difference between AngularJS, ReactJS and Nodejs?

·         Angular JS is a front-end framework and can be used with any backend programming language like PHP, Java etc. whereas Node JS is simply a server-side language, in a web application like context it acts as a Java on the server side. ... Angular JS runs on the client browser whereas Node JS runs on the server side.

·         AngularJS is fully featured framework than ReactJS, which is not really a framework but a library. ... However, AngularJS has a large support community and following while React is just getting started. On the other hand, Nodejs is simply a JavaScript runtime which is lightweight and fast.

Java 8 experience • SQL (MySQL or PostgreSQL) and NoSQL (MongoDB or Cassandra) • Cloud Infrastructure • JPA and ORM frameworks • 3 years + using Spring Framework • Able to create RESTful APIs • Agile, Scrum, Kanban, Junit, Mockito • Building micro services (Spring Boot) • JavaScript (NodeJS, AngularJS, ReactJS) • Object Orientated programming and designs • Full Stack Development Desirable Skills • Docker • Jenkins, GIT, Maven, Jira etc • Elastic Search, Logstash, Kibana

Summary:

·         Expertise in the web application development using HTML 5, CSS 3, JavaScript, jQuery, AngularJS, Angular 2, Angular 4, Typescript, ES6, ES7, ReactJS, NodeJS, ExtJS, BackboneJS and Bootstrap.

·         Extensively worked on n-tier architecture systems with application system development using Java, JDBC, JSP, EJB, Servlets, Struts2, Spring Framework, Hibernate, JPA, JSTL, JSF, JNDI, JMS, JavaScript, Web services, WSDL, REST, SOAP, and XML.8

·         Extensive experience in design and development of J2EE applications using Core Java (J2SE 1.7), Java Collection Framework, Swing, JDBC, JDK, Servlets, JSP, EJB, Spring Framework, Hibernate, Struts, Web services, WSDL, REST, SOAP, Enterprise Java Beans, XML, XSLT, Java Beans, and JQuery.

·         Experience in developing and a solid understanding of SOA and Microservices Architecture.

·         Strong experience in working with Relational databases like Oracle, MySQL, Microsoft SQL Server, PostgreSQL and NoSQL databases like MongoDB, Apache Cassandra

·         back-end RDBMS tools like Oracle 9i/10G and MySQL.

·         Strong experience in implementing MVC framework like Struts 2.0, Spring 2.x and ORM tools like Hibernate in J2EE architecture.

·         Strong Knowledge of Object Oriented Design Methodologies such as Polymorphism, Inheritance and Encapsulation.

·         Experience in developing Android application using SQLite, Java, Mobile JQuery, Eclipse IDE,Android Studio, Android SDK and ADT plug in.

·         Experienced in build tools like Ant and Maven, Log4j for Logging and jUnit for testing.

·         Experience in implementing the MVC architecture in backend applications using Node.js along with ExpressJS that interacts with MongoDb and performed CRUD operation on MongoDb.

·         Proficient in working across all stages of Software Development Life Cycle (SDLC) and Agile methodologies.

·         Expertise in using J2EE Application Servers such as IBM WebSphere 4.x/5.x/6.x, WebLogic, JBoss 3.x and Web Servers like Tomcat 5.x/6.x

·         Extensively used IDE for Application development like RAD 6.0, Eclipse3.x, Net Beans

·         Experiences with build tools include Maven, Gradle and Jenkins Version.

·         Development experience includes working with cross functional team and global development teams in Onshore/Offshore Model.