Java

JavaOne 2017

— Maarten Mulders

This year, I had the pleasure again to visit JavaOne. Not only did I attend the conference, I was also accepted to speak, which was quite a dream come true. The session catalog contains almost 500 sessions, and I obviously visited only a subset of them. I found two topics particularly interesting and decided to attend multiple sessions on each of them. “Prepare for JDK 9” and “Migrating to Java 9 Modules” Both sessions where more or less covering the same ground, although from a different perspective.

JBCNConf & Voxxed Days LU

— Maarten Mulders

Wow, that was a busy and inspiring week! In one week, I’ve visited two conferences in two different countries to give talks on two different subjects. But the most inspiring part came from attending other sessions. I’ll highlight one session from both conferences. JBCNConf 2017 On JBCNConf, I’ve attented a session by Burr Sutter about Vert.x. This was a session full of energy, as Burr is really capable of making your enthusiastic of whatever he is talking on.

Verify logging with Logback

— Maarten Mulders

Sometimes you have a piece of logging that is very important, maybe even part of a business requirement. In that case, you might want to verify that in a unit test, so you can rest assured that this requirement is actually met. How to do that? Mock it away A first approach might be to just mock your logging framework in a unit test and verify it was called as you expected.

Blah blah Microservices blah blah

— Maarten Mulders

As a closing keynote on the second day of Jfokus, Jonas Bonér took the stage under the very clarifying title “Blah blah Microservices blah blah”, which turned out to mean “From microliths to microsystems”. As a first observation, he stated that no-one really likes microservices. They are kind of a necessary evil - because “doing” microservices comes at a cost. In fact, microservices are just a specialisation of an older concept called distributed systems.

Jfokus, Day 2

— Maarten Mulders

The second day of Jfokus is just as action-packed as the first one. However, part of the action is me giving two talks. Both of them scheduled today, so a little less time for attending other sessions and blogging about them. I did attend some other sessions after lunch time, on which I’ll report below. Introduction to Machine Learning Directly after the lunch, James Ward gave an introduction to machine learning.

Quickly switch Java versions on macOS

— Maarten Mulders

Inspired by a Jfokus session I attended today I decided to download and install a preview of Java 9 on my MacBook. That went pretty quick and without much trouble. But when I issued java -version on my terminal, I was greeted with Java(TM) SE Runtime Environment (build 9-ea+155) Java HotSpot(TM) 64-Bit Server VM (build 9-ea+155, mixed mode) Although that’s nice - you’d even expect it, maybe - I realised I often need Java 8 as well.

Jfokus, Day 1

— Maarten Mulders

These days, I’m in Stockholm, attending and speaking at the Jfokus conference. Yesterday night was a great opportunity to get to know a few other speakers during dinner. We were even surprised by an act of the Lemon Squeezy barbershop quartet singing for us - very beautiful! But today, the serious stuff started. In the following sections, I have written down my notes and observations of each of the sessions I attended.

Automatic scan for known vulnerabilities in dependencies

— Maarten Mulders

When using third-party components (be it open source or not), we all know it’s a good practice to keep your frameworks and libraries up to date. This is also one of the spearhead in the OWASP Top 10 (2013 edition): A9 - Using Components with Known Vulnerabilities. To help you assess your projects status with regard to this, OWASP.org developed the tool Dependency Check. This tool is primarily intended code bases in Java, .NET, Ruby, Node.js, and Python. Integration with various build tools is also provided for.

Easily upgrade Java dependencies

— Maarten Mulders

To start with a cliche: the Java ecosystem continues to develop at a high pace. Various open source frameworks releasing versions, sometimes even multiple versions at the same time. This may quickly turn into a risk But how to deal with it? Basically, you have two options. We’ll take a typical Maven-project as an example, which uses Commons Lang 3. See the end of this post if you prefer Gradle over Maven.

This method is likely to yield significantly better performance

— Maarten Mulders

This week, I came across an interesting difference between the Java API documentation and its current implementation. A difference? Or is it just a matter of thorough reading? If you look at the Javadoc for Double.valueOf(), you’ll find that it is likely to outperform the use of new Double(). Sounds good! And don’t we all ove it when we get a free performance boost? However, examining the source code to see what causes this “significantly better space and time performance”, we find….