This february I gave a talk on Mahout clustering at FOSDEM 2011 where I demonstrated how to cluster Seinfeld episodes. A few people wanted to know how to run this example so I write up a short blog about it. In just a few minutes you can run the Seinfeld demo on your own machine.
Gimme all resources you have – I can use them!
Exploiting full IO and CPU concurrency when indexing with Apache Lucene During the last year Apache Lucene has been improved an extreme amount with outstanding improvements such as 100 times faster FuzzyQueries, new Term-Dictionary implementation, enhanced Segment-Merging and the famous Flexible-Indexing API. Recently I started working on another fundamental change referred to as DocumentsWriterPerThread, an […]
Debugging the dreaded “SEVERE: Error listenerStart” and “SEVERE: Error filterStart” tomcat error messages
Just a quick post that I hope might benefit others. If you have been developing web applications on tomcat for a while you have likely come the two error messages mentioned in the title: SEVERE: Error listenerStart and SEVERE: Error filterStart. SEVERE: Error listenerStart Occurs when an exception is thrown in the contextInitialized method of a ServletContextListener […]
Getting GWT to work with Servlet 3 Async Requests
For one of our projects, we use a GWT client that needs to be updated in near-real time (< 1 second delay) when something relevant happens on the server. There are multiple ways of doing it, but I tried to get it working with the new Servlet 3 feature: Asynchronous Http Request handling. Read on […]
Using Hamcrest Matchers.everyItem
For my Junit test I wanted to make use of Matchers.everyItem so I could easily check if every item of a list machtes a certain matcher. Resulting in a small line of code which is nice to read.
Mahout at FOSDEM 2011 DataDevRoom
Last saturday, february 5th, FOSDEM 2011 hosted the DataDevRoom where talks were given on topics surrounding data analysis with free and open source software. I was there and gave an introductory talk on clustering with Apache Mahout. In case you missed the conference, read on to learn about some of the talks or checkout the […]
Using the Spring RESTTemplate with Jackson
About a week a go I wrote a blog post on gridshore about the NOS open data API. Most of the technical items are explained in that post. In this post I want to tell you about the small library I have created around the NOS open data REST based API. With this client it […]
Logging to the syslog from a java application
Every application needs logging, it can help you during development and when debugging those annoying things that do not work in production. One question is where to put the logging events. All linux servers use a system log to log events that take place on the operating system level. You can find logs for the kernel, […]
Easier mocking with Mockito
If you have been happily using Easymock for the past years, this blog post is for you. Because you need to upgrade to Mockito, the new kid on the block in the mocking universe. Why bother about what mocking framework you’re using to create your unittests? Because it will improve you tests, make them more […]
Bean Validation: Integrating JSR-303 with Spring
I recently had a chance to actually use the new Bean Validation spec. in one of my projects. As the developer of the Bean Validation Framework for Spring (part of the springmodules project) it of course feels a bit weird to ditch all the work I’ve done, but at the same time, it also feels […]