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Author Archives: JJ

Jean-Jay Vester graduated from the Cape Peninsula University of Technology, Cape Town, in 2001 and has spent most of his career developing Java backend systems for small to large sized companies both sides of the equator. He has an abundance of experience and knowledge in many varied Java frameworks and has also acquired some systems knowledge along the way. Recently he has started developing his JavaScript skill set specifically targeting Angularjs and also bridged that skill to the backend with Nodejs.

ByteCode primer for Java Class Files

It is often stated that to be good at the programming language you code in, one should at least dig and understand one abstraction level lower than the one in which you are coding. For Java, that would be the JVM, which would imply byte code. In this article we will kick start our adventures in Java byte code. Byte ...

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Java Servlet and JSP Example

In this article we will demonstrate a simple Servlet and JSP example using the maven cargo plugin from the command line. We will also cover, albeit briefly, the functioning of both Servlet and JSP constructs within the Servlet Container in terms of how they are used to satisfy a HTTP request. The sample application will greet you with your name, ...

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Java Servlet Container Example

In this article we will demonstrate deploying and running a simple web application via a servlet container. In addition to demonstrating how to run the sample web application using a servlet container will also show how to run the sample web application using maven from the command line. For this article we will make use of Tomcat 8.5.x both for ...

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Java Nio FTP Example

In this example we will demonstrate an FTP example program written in Java using some of the NIO features available to us. The example program will take the form of a command line program which accepts 2 arguments, namely the FTP location to transfer the file from and the local destination on the file system, inclusive of the file name, ...

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Java Servlet XAMPP Tutorial

In this article we will briefly discuss what Xampp (Apache + MariaDB + PHP + Perl) (pronounced “shamp”) is and how to “run” a Java Servlet application from it using linux. I use the word run in the loosest possible sense as the Servlet application will actually be driven from inside Tomcat which will be proxied to from Xampp or ...

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Java Servlet Websocket Example

In this article we illustrate a simple chat program using a Websocket endpoint. The Java API for websocket provides both client and server api’s and can be found in the javax.websocket javax.websocket.server packages accordingly. The example article will do a brief dive into the mechanics of Websockets from a Java perspective and then it will demonstrate some of it’s mechanics via a ...

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Java Servlet Generate Zip File Example

In this article we illustrate how to generate a zip (compressed) file via a GET request to a custom servlet. The servlet will serve said file (configurable via a WebInitParam) to the browser and the browser will then prompt the user with a download prompt to save said file to the file system. The file will be served asynchronously using FileChannels transferTo(...). ...

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Basics of Servlets Tutorial

In this article we will cover the basics of Servlets using Java 8, in a servlet 3.1 compliant container. We will demonstrate some of the basics of servlet usage in a Http context, via a simple web project that combines numerous simple example servlets all accessible via your favorite browser or via postman. Table Of Contents 1. Introduction 2. Technologies used ...

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Java 9 JDeps Example

In this article we cover the JDeps tool using Java 9. We will use a simple multi-module maven project and demonstrate some usage scenario’s (filtering and aggregating) of JDeps using said project. We will also make use of an online service to show how we can better visualize reports generated by JDeps. Prior to digging into the usage of JDeps on ...

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Java 9 Reactive Streams Example

Spurred on by an abundance of non-standardized Reactive Stream implementations for the JVM (Akka streams, RxJava) and an increasing need to handle stream related problems in a reactive manner, JEP 266 was augmented with the need for an interoperable publish-subscribe framework that sought to standardize reactive streams solutions for the JVM. This way library implementations now have a standard that ...

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