This repository contains a set of examples related to the testing, security and development of enterprise systems. Currently, this repository focuses on Java/Kotlin, targeting frameworks like Spring and Java EE.

The material in this repository is used in two university-level courses at the university college Høyskolen Kristiania. In particular:

• PG5100 Enterpriseprogrammering 1: introduction to enterprise programming. Documentation here.

• PG6100 Enterpriseprogrammering 2: advanced enterprise programming. Documentation here.

The repository is built with Maven, and it is divided in two main sub-modules:

• intro: material used in the first PG5100 course, where the goal is to be able to build a web application accessing a SQL database, and deployed on a cloud provider. Main technologies: Java, JEE, JPA, EJB, JSF, WildFly, SpringBoot, Spring Security, Selenium, Docker.

• advanced: material used in the second PG6100 course, where the goal is to dig into the details of web services and micro-service architectures. Main technologies: Kotlin, SpringBoot, REST, GraphQL, React, Docker, Spring Security, Spring Cloud, AMQP.

For building GUIs, the second part of the course advanced relies on knowledge of JavaScript and Single-Page-Applications. This is covered in a different course, called Web Development and API Design (PG6301). Such course should be taken before the advanced one (PG6100), in parallel or after the intro course (PG5100).

Before taking these courses, you might want to refresh your knowledge of algorithms and data structures (e.g., PG4200), as those are widely used here (e.g., maps, sets and streams).

There are many resources (e.g., courses and books) out there that deal with the development of enterprise/web systems, using different technologies (e.g, Java and C#). However, often such resources only deal with the development of these systems, whereas important concepts like testing and security are treated like just secondary concerns, if treated at all. This situation has been improved in recent years, but more could be done, and we hope that the courses in this repository are a step in that direction.

There are plenty of applications out of there that are afflicted with bugs and security holes. Correctness and security should play a major role when developing software, and we try to reflect it in this repository.

Furthermore, software engineering is a practical discipline, like any other engineering discipline. As such, although theory is important, it is also important to get your hands dirty by actually developing software, and putting theory into practice. Therefore, in this repository, all concepts are explained also via examples, with test cases (unit and integration/system ones). In other words, we follow the principle of Code is King, i.e., if something is worth discussing, then you must have a working example with test cases for it. In the past, it would had been a problem when you had to download and configure all needed software manually, like for example a PostgreSQL database or a RabbitMQ server. Fortunately, with the coming of Docker, this is not a problem any more.

In this repository two languages are used: Java and Kotlin. Also two different frameworks are used: Spring and Java EE. Why such choices? When studying the concepts of enterprise software development/testing/security, the actual used languages/frameworks are not so important. The languages/frameworks are just used to get practice, and get your hands dirty. For example, using C# with .Net would had been a viable option as well. When you get a degree in software engineering, by all means afterwards you could end up working with C#/.Net and never touch Java again. Therefore, it is important to learn the fundamental concepts behind those languages/frameworks, and not just their low level technical details.

Trying and getting some experience with all the main languages and frameworks would be good. However, when studying such topics for a university degree, time is limited, and one needs to make some choices. And switching between too many languages/frameworks would just be a too large overhead (e.g., learning different IDEs and building tools). The motivation for the choices of languages and frameworks in this repository is as follows:

• Java: one of the most used programming languages, with a very large ecosystem of existing applications and libraries. Java is one of the main languages for enterprise development (if not the main language). Enterprise systems are often large and complex, and so a statically typed language is recommended. In our personal opinion, this excludes languages like JavaScript, Python, Ruby, etc. TypeScript is statically typed, but it is still JavaScript in its core...
  Nowadays, C# is a good option, and as a language might even be considered better than Java. On one hand, it does not have as large ecosystem as Java. On the other hand, considering the bullshit of Oracle's new 6 month release cycle, .Net seems a more open-source friendly option (depending on how effective adoptopenjdk.net will be). Note: stating something like this before 2010 (when Oracle bought Sun) would rightly grant you a single way ticket to your local asylum. So strange to see how much the computing world has changed since the Java Zone Trailer and Lady Java videos came out.

• Kotlin: our language of choice. It is a better Java that can reuse all of its existing ecosystem. However, it does have more abstractions and "magic" than Java, which arguably means that it is not suited to learn as first language, i.e., better to learn Java first. That is the reason why it is only used in the advanced course, and not the intro one. Furthermore, job-wise, Kotlin is not so popular yet, although there are some interesting cases (e.g., the Tax Department of Norway using it for their backend development, with few systems open-source on GitHub).

• Spring: our framework of choice. SpringBoot is simply great. It does have a non-trivial learning curve though. However, once you understand the concepts of dependency injection and proxy classes, it is a great tool. For the development of web services, DropWizard can be a good choice as well, especially if you do not like the "magic" of Spring and want a more direct/explicit library.

• Java EE: in theory it was the "official" Java framework for enterprise development. But Oracle (owner of Java) donated it away in 2017, and now it is called Jakarta EE. Anyway, in our opinion, it is much worse than Spring. Job-wise, at least in Norway, it is used less and less. Still, it is important to look at different frameworks. As the jump from Java EE to Spring is relatively simple, it is a good choice as starting point before moving into SpringBoot. Furthermore, you cannot really appreciate SpringBoot until you have gone through the blood, sweat and tears of debugging an EJB test using Arquillian to deploy to a WildFly container.

Current documentation is available here for the intro course, and here for the second advanced course.

• JDK 11 (download it from https://adoptopenjdk.net/, do not use the JDK from Oracle)

• An IDE (recommended IntelliJ IDEA Ultimate Edition)

• Maven 3.x

• Docker

• Chrome and Chrome Driver (only needed to run Selenium tests locally instead of in Docker)

• YARN and NodeJS

The code in this repository should run on all major operating systems, i.e. Mac, Linux and Windows.

On Windows, if you have problems with too long file names when checking out the code with Git, then you might need to run the following command on a terminal:

git config --system core.longpaths true

• mvn clean install -DskipTests

  this will compile all the code and install all the generated jar files into your local Maven repository. Does not run the tests. Note: first time your run it, it might take a long while, as needing to download many dependencies.

There are many ways in which you can contribute. If you found the material in this repository of any use, the easiest way to show appreciation is to star it. Furthermore, if you find issues, you can report them on the issues page. Possible types of issues:

• Some of the code examples are unclear, or with not enough documentation to understand exactly what is going on.

• You find a non-intended security vulnerability or bad practice in any of the code examples. Note: in some cases, for didactic reasons there will be non-secure code. But in those cases that should be explicitly stated.

• Comments regarding a tool/library/framework are no longer valid (e.g., since a new version has been released).

The materials herein are all Copyright (c) of Andrea Arcuri and contributors. The material was/is produced while working at Westerdals Oslo ACT and Høyskolen Kristiania.

All the source code in this repository is released under LGPL version 3 license.

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