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Category Archives: Technology

Enterprise Technologies

Spring Core Basics

23 Feb

Episode 58

This week I was planning to publish introduction to Amazon Web Services, but since I’m working on preparing Spring-based web applications development course for Wrocław University of Technology students with my two colleagues, I decided to change the schedule a bit. I planned to write few articles about Spring framework anyway, but in order to fit everything before particular classes in March and April I need to start exactly now.

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I wrote a Spring Hello World article over two years ago actually, but today I wanted to talk a bit more about some fundamental concepts: Inversion of Control and dependency injection. Let us take a closer look at application structure, configuration, components and wiring. There will be quite a lot of code snippets. If you would like to play with complete application working out of the box, visit my GitHub project Spring Angular Intro. The application is based on the one I prepared for Angular Intro article in September 2016, but now we will focus on back-end exclusively. This tag corresponds to project state at the time of writing this article.

Concepts

Classic approach to program structure is that we write custom, high-level code which calls lower level code.  The flow of control goes from our code to a generic framework or libraries. Inversion of control is a technique, where Read the rest of this entry »

 
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Posted by on February 23, 2017 in Spring, Technology

 

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Cloud Computing Intro

16 Feb

Episode 57

Last week we talked about virtual machines and containers and rapidly growing popularity of the latter. Another subject that people in software development talk a lot is the cloud. Everyone wants to be in the cloud nowadays, there is a number of good reasons to do that and some reasons not to.

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Originally, I wanted to write an introduction to Amazon Web Services this week, since I’m into this topic recently. However, I realized that the introductory paragraph about the cloud in general is growing too fast and it requires a separate article. Let’s start with a bit of history of cloud computing. Remember: There is no cloud. There is just someone else’s computer.

Cirrus: Long Time Ago…

After the initial developments in computing technology, in sixties and seventies, it was typical, that organization had one large computer, the mainframe, and people were connecting to it over the network using terminals, just to send data and receive results. Then, there was the microcomputer revolution, and Read the rest of this entry »

 
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Posted by on February 16, 2017 in Cloud, Technology

 

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Virtualization and Containers Intro

09 Feb

Episode 56

Container revolution is one of the hottest topics nowadays in software development industry. The little blue whale, the Docker logo, can be seen on most programming conferences as well as numerous Twitter feeds of, so called, IT influencers.

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Today, along with containers, we will talk about their older and fatter siblings: virtual machines. It’s good to understand similarities and differences between those two and how to take advantage of that. We will talk about what containers are and what they are not. Contrary to what might have seem, containers did not render virtual machines entirely obsolete and there are reasons to use both.

Virtual Machines

Virtual machines are emulations of computer architectures and provide functionality of a physical machine using appropriate combination of software and hardware. It’s not a new concept, as first implementation dates back to systems developed in the sixties like IBM CP-40. They are commonly used to Read the rest of this entry »

 
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Posted by on February 9, 2017 in Cloud, Technology

 

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From Java Source to Bare Metal, Part Four: The Battle of Eight Cores

12 Jan

Episode 52

This is the fourth and final episode of our little Hobbit’s journey through layers of abstraction of web application and all its foundations down to hardware. Starting in episode 49, we traveled all the way from Java code, web framework, web server, Java virtual machine, container, operating system through Internet Protocol Suite. It’s time to meet the Bare Metal.

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The Hobbit paced across maze of corridors and shafts inside the mountain to finally emerge through the main gate and run down the valley to breathe a fresh air. A moment later he froze, turned around, looked up and realized his grievous mistake. The Physical Dragon was not above the Lake City anymore. He was lurking at the mountain side, just above the gate, piercing terrified Hobbit with his gaze.  

Fire and Water: The Bare Metal

Everything we talked about up to this point was basically software. Now it’s time to look into our Hobbit whereabouts from the physical machine point of view. We started with an assumption, that we have a reference to the Hobbit object in our Java code. The object lives on Read the rest of this entry »

 
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Posted by on January 12, 2017 in Technology

 

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From Java Source to Bare Metal, Part Three: The Networked Mountain

05 Jan

Episode 51

Hello traveler. Today we are continuing our journey through abstraction layers in a web application with all its foundations. Two episodes ago we started from Java code written by hand, followed by the web framework. One episode ago we went down into web servers, traveled through Java virtual machine to finally meet the container engine. Finally? Oh no, there is still long way before us.

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The cruise on the back of giant blue whale is over, and the Lonely Mountain is closer than ever. The Hobbit jumps out of the barrel and lands on solid ground somewhere in the city harbor. Meanwhile, the whale drifts away, unnoticed by busy workers. The hobbit leaves the dock and treads towards the building that dwarfs nearby ones with its size. The city hall.

On the Doorstep: The Operating system

In terms of the operating system, we are now crossing the border between the application and the kernel. We can say, that both sides were mediated by the container engine, which presents virtual kernel API to the application inside the container and maps all calls to the actual kernel API on which it resides. Java virtual machine and everything that’s sits on top of it, is now just another Read the rest of this entry »

 
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Posted by on January 5, 2017 in Technology

 

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From Java Source to Bare Metal, Part Two: The Desolation of Bytecode

29 Dec

Episode 50

In the previous episode, we started a journey through layers of abstraction of modern back-end web application. As a response to unexpected request, a Hobbit object is going to an adventure, and must travel safely across the technology stack. We seek an answer to the question what happens between Java code and the physical machine. Perhaps, even further.

Our Hobbit leaves the, yet familiar, plain of web framework and goes deep down under the Misty Server Mountains.

Riddles in the Dark: The Server

The code sits atop of web framework, and web framework sits atop of web server. That was mostly true until recently. Now, with Spring Boot, it is common that instead of deploying packed application to the server, there is a fat jar that contains embedded server inside an application. No configuration, no deployment, just running a single jar. Simple solution for simple problems, but of course it’s no silver bullet and might not fit everywhere. How does the server and the application fit together?

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There are different tiers of servers, as I wrote some time ago. The largest that we care about are application servers, like Read the rest of this entry »

 
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Posted by on December 29, 2016 in Technology

 

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From Java Source to Bare Metal, Part One: An Unexpected Request

22 Dec

Episode 49

Imagine you are developing a web application based on a typical modern technology stack. In essence, the goal is to create something that receives requests from the network, processes them, and responds to them with some kind of structured data. It can be a fancy HTML webpage to be displayed in client’s web browser or it can be a raw text object to be consumed by another application web API. Have you ever wondered what exactly is going on behind the scenes? What is happening between the moment when the code you wrote is executed and the moment when electrical impulses jumps the network cable sticking out of that metal box in the data center? Let me take you on the journey along numerous layers of abstraction in modern software stack that must be bypassed to make things happen.

There and Back Again: Abstractions

Programming is all about abstractions. We endlessly put one layer above the other in order to deal with tremendous complexity of software and hardware. Often, we ignore most of the layers to focus on solving the actual problem at hand. In principle, sending a JSON object over the network might seem like an easy task with modern tools and frameworks. You generate the project, tweak just a little bit here and there, write one method with few annotations and there you go, it works. But the engineering problem of making this possible in an easy, fast, secure, reliable, scalable and manageable way is gargantuan. Looking at the big picture, it’s probably an effort of hundreds of thousands of software developers, architects, electronic and electrical engineers, computer scientist and mathematicians, spanned over several decades of work. All that, to let you do the job in a single pomodoro.

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Of course, to develop decent software, you don’t necessary have to understand exactly how all this works, it’s probably not even possible for a single human being to grasp all that in every detail. I believe however Read the rest of this entry »

 
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Posted by on December 22, 2016 in Spring, Technology

 

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Software Talks Rzeszów Dec 2016 and banking apps security

15 Dec

Episode 48

Software Talks is a recurring event organized by PGS Software, consisting of tech talks, beer, pizza and a lot of fun. Some time ago I wrote about the two September editions in Wrocław and Gdańsk, in which I took part as a speaker. On December 8th there was another event, this time in Rzeszów, a city located in south-eastern Poland. I was a speaker for the third time in a row, but for the first time with my colleague Tomasz Zieliński, who recently made a lot of noise in Polish banking environment, preparing a report, which exposed several critical security issues and other major problems in their mobile banking applications. If you read my article about working for different types of companies, you might have noticed that I’m not a big fan of banks’ approach to software development, so I’m going to elaborate on Tomasz findings without mercy.

Background

Last time on Software Talks I spoke with Piotr Konieczny, Polish security expert. This time there was an idea to focus more on Java / software development topics, so I was on a mission to find a second Java speaker. I found one, but at the last moment some issues appeared and he couldn’t make it, so his place was taken by Tomasz, who is actually our Android expert.

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It was kind of a busy week for me, as I was three days in Berlin with our client, arrived in Wrocław on Wednesday evening, and an hour later I was in a car with Read the rest of this entry »

 
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Posted by on December 15, 2016 in News, Technology

 

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API management tools

08 Dec

Episode 47

Long time ago, the Internet was full of proud and secluded applications, that relied on themselves to provide service. However, services were becoming more and more complicated, also technologies and protocols for connecting with other applications became more standardized. It became obvious that collaboration and specialization is required to survive. Applications thus started to be more specialized, talk to each other much more, and the level of digital interconnection skyrocketed. Along with that, did the market of solutions for managing web APIs.

Do I need API?

Most likely you do. Imagine a big corporation that is building HR system. They want the module related to business travel for planning and reporting. Is there a point in writing everything from scratch? If you plan travel, let’s ask someone who is already good at it. If you want to buy a ticket from A to B, there are companies that provide travel meta search service, both via website and API.

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Those companies need data, so they ask someone who possess it – bus and train operators, airlines, car rentals and perhaps other travel meta search companies. Maybe, when planning travel, especially the end points, we might want to specify an address. How do we know that address is correct? We should ask someone who Read the rest of this entry »

 
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Posted by on December 8, 2016 in API, Technology

 

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FutureDevDay Gliwice 2016

01 Dec

Episode 46

On November 25th I attended a small conference organized by Future Processing in Gliwice. We get there, me and my two friends, in less than two hours of driving from Wrocław. The conference was held in a really lovely building within a complex of Upper Silesian Agency for Entrepreneurship and Development. Few hundred developers gathered for a single track composed of 11 talks 25 minutes each and finally a special guest talking for an hour.

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At the end, there was an after party in a nearby bar (called “progress bar”, how cute!) with three discussion panels, food and beer.

Talks

Talks were grouped thematically into categories composed of two or three each. First were architectural ones, then frontend, cloud and finally big data. I decided to write more about few sessions I liked the most and to take liberty at titles translation, if required. Let’s start with Read the rest of this entry »

 
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Posted by on December 1, 2016 in News, Technology

 

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