I used to see Optional<Something> as a completely useless addition to Java, adding to the bloat of Java without being any clearer than checking if a reference is null.
I have changed my mind, and now think Optional<> can be useful in making code simpler, easier to understand, and more robust.
The reason I changed my mind, was the usefulness of Optional.orElseThrow() when having to traverse deeply nested data structures in Java code.
Mastodon is a social network that appears similar to twitter: you get a feed where you can see “toots” instead of “tweets” and you can send your own toots that will be seen by others listening to you or looking for a hashtag found in your toot. Continue reading Join mastodon and slowly posting a wordpress RSS/atom feed
Diaspora is a social network that appears to similar to Facebook in its behaviour: you get a web UI with a feed, and what ends up in that feed comes from your friends and your groups and what hashtags you filter for.
I create web applications by first creating a set of OSGi bundles that form the building blocks of the application, and then use karaf features to pull the building blocks together to create complete applications that run inside apache karaf.
In the start of January 2020, the test coverage percentage on all sonarcloud projects suddenly dropped to 0%.
This blog post explains why coverage percentage dropped to 0% and how to get the test coverage back in the sonarcloud reports.
The JerseyServlet simplifies the approach outlined in Use Jersey to provide REST APIs from karaf applications.
Continue reading Simplified REST APIs from karaf using Jersey
OSGi is a Java plugin framework and module system that were initially created for supporting embdedded applications in the automotive industry. OSGi also forms the foundations for the Eclipse IDE plugin model. The plugin model of OSGi consists of components waiting for services and starting and exposing services when all of the dependencies are satsified. A “service” in OSGi terminology, is a Java interface.
I first encountered OSGi in 2006. The company I worked from used OSGi as the basis for an ETL processing system implementing various processing elements as OSGi plugins plugging into the processing framework. Since writing OSGi activators (which was the state of the art for OSGi plugins back in the day) is kind of boring, we created a Dependency Injection system on top of OSGi.
After creating the post Pluggable databases for apache karaf applications I posted a link to the blog post in the karaf user mailing list, and the immediate response was, “why didn’t I just pax-jdbc-config instead?“.
The answer to that is that I didn’t know about pax-jdbc-config. I started using pax-jdbc in the summer of 2016, and started using apache karaf in the autumn of 2016 and pax-jdbc-config didn’t exist then (or at least: not as complete and usable as it became in 2017), and any announcement that has gone past since then, has not registered.