Notes about learning Elixir
When I first heard about Elixir at Øredev 2012 I thought it was nice, but I didn't really get it. I remember thinking than Elixir was like Ruby for the…
Java 8 Collector for Gauva’s LinkedHashMultimap
10 months ago or so I wrote a blog post entitled Immutable List Collector in Java 8 (that probably should have been named "Unmodifiable List Collector in Java 8" to…
Asynchronous Spring Service
It is not unusual that your web service needs to communicate with another web service in order to serve its clients. In the old days, that would imply that an…
Spring Boot custom HealthIndicator
A big part of the DevOps responsibilities is to monitor and maintain the health of running servers. If a production server goes down, appropriate actions must be undertaken to bring…
Integration Testing a Spring Boot Application
Spring Boot brings about some welcome defaults configurations that significantly decreases the development time of Spring projects. It also has some useful additions when it comes to simplified integration testing.…
‘Default’ Oracle JVM Flags
Launching a Java Virtual Machine can be as easy as running java -classpath myapp.jar Main or even shorter java -jar myapp.jar if your using the Main-Class attribute in META-INF/MANIFEST.MF. This…
Sandboxing plugins in Java
Some Java applications need to be able to load plugins, in the form of .jar files, from untrusted sources, and execute code from such plugins with restricted permissions, for example…
Using RxJava to Monitor Hystrix Streams
When working with distributed systems it's important to take failure into account. The book Release It! is a great book for learning how to deal with some of these issues.…
GeeCON 2014
Last week we visited the GeeCON conference in Krakow as speakers and participants. The event attracted some 1200 visitors according to the organizers, and it was located inside a cinema…
Async Servlets
It is now about four and a half years since the Servlet 3.0 specification was released in December 2009, together with Java EE 6. One feature that came in Servlet…
Java 8 and AssertJ support in Awaitility 1.6.0
Awaitility is a library for Java (with extensions for Groovy and Scala) to test asynchonous systems. The 1.6.0 release introduces support for AssertJ assertions as well as better Java 8…
Custom metrics with New Relic
We have a stand alone Java application (called MyApp here) that runs an embedded Jetty HTTP server that we wanted to monitor. It was surprisingly easy to get basic information…
Java Properties with the Owner framework
In virtually all projects you need to read properties from external sources such as a file. In many cases you also need to be able to override some properties when…
About ExecutorServices
Dealing with asynchronous programming is not easy, at least not if you are a Java programmer. Not only do you have to take care of Callables, Runnables, Futures and likes,…
Spring @PropertySource
If you are a Spring developer and and you have created a Java based container configuration, you have probably come across the @PropertySource annotation for importing resources. It was first…