November 22, 2016

Visual Search applied – the “Fashion-Cam”

Artificial intelligence features are slowly becoming industry standards in modern products and services in every niche. Now, they are being integrated into the willhaben Fashion-Cam. The visual search project, originating from the Styria Innovation Incubator, provides a cutting edge system to add machine learning methods to existing search agent features. This empowers users to search for classified ads using photos of interesting products using either a photo taken by the user, or one from an existing ad.

November 07, 2016

Mutation Testing – Integrating into a large (legacy) application

This blog demonstrates the concept of mutation testing on real-world examples. It tries to show how it can be integrated into an existing large (legacy) code base and how it impacts the build time. Based on this information, I want to give you some ideas about how mutation testing can be introduced in your applications.

October 12, 2016

Performance at its (CPU-) Core

Who should read this?

This article will be interesting for you if you:
    • Are trying to decide which hardware to buy;
    • Are designing a service that is supposed to run on a specific hardware specification;
    • Are an operator like me; or,
    • Generally like to fiddle around with hardware and tune system performance.

    October 04, 2016

    Launching a new product – from zero to native couponing

    Recently, we successfully launched native couponing in our Android and iOS Apps. Providing coupons with discounts in various areas provides benefits to the approximately 1 million people who use our mobile services on a regular basis. Our users collected more than 15,000 coupons in just the first couple of weeks after launch.

    Launching a completely new product is always a challenge, especially if you have a lot of stakeholders – product managers, digital advertisers, sales people, developers, quality assurance specialists, etc. just to name a few. All of them are involved in building great products for our users.

    From the viewpoint of a technical project lead, it is challenging to meet all the functional and non-functional requirements. This blog post shows how we bootstrapped a new product from the technical side, from zero to getting it into production; which technology we used; which architecture fits our requirements; how we embedded it in the existing infrastructure; and, most importantly, what to avoid. This article will cover these topics at a high level and will not provide any implementation details.

    September 28, 2016

    Parallel Streams

    The Streams API that came with Java 8 enabled functional programming by taking advantage of the new lambda functionality and the method references. One of the most popular features of streams is that they support lazy evaluation. Another very popular feature of streams is that they are capable of processing results concurrently using multiple threads. In this article, we will examine the main points to consider when using a parallel stream.

    Creating a parallel stream is really simple; you just have to designate that your stream is parallel and the operations are done in parallel automatically for you. There is no need to write any threading code to make it happen. There are 2 ways to create a parallel stream: you can either create it from an existing stream, by calling the parallel() method, or use an extension method that has been added to the Collection interface, as below:
     Stream<String> stream = Stream.of("cat", "dog");  
     Stream<String> parallelStream = stream.parallel();  
     Stream<String> parallelStream2 = Arrays.asList("cat", "dog").parallelStream();  

    September 27, 2016

    Optionals in Java 8 and How to Use Them

    Since the release of Java 8, NullPointerExceptions have been pretty common. Before Java 8, your code was probably full of "if statements" to check if a variable was null. Still, it was impossible to catch every NullPointerException out there. With Java 8, Oracle attempted to solve this issue. They didn’t invent the holy grail, but they did make our lives as developers much easier by helping prevent code smells and those nasty Exceptions. Now, if you start a new project, you should definitely use Java 8 to avoid NullPointerExceptions.

    So what exactly did Oracle do to help us in our misery? They introduced Optionals. [1]

    You may have heard of Optionals already a few times, but you maybe dont know exactly know how to use them in the right way. If you use them in the wrong way, it is like you wouldnt use Optionals at all. So let's take a look how Optionals could be used.

    Java 8 Date and Time API [Quick Introduction]

    Along with new language features like lambda expressions and streams, Java 8 has also introduced a new concept to deal with dates and times. Working with dates and times prior to Java 8 was a little tricky and cumbersome, which led to the popularization of third-party time libraries like Joda-Time. Even for those starting to learn Java with version 8, it is still important to be able to understand the code written the old way. In this article, we will examine the core differences between the old and new way.

    First of all, in order to use the new classes, import the java.time package like this:
     import java.time.*;