ID trouble with multiple Hibernate entities on the same table

Just a while ago I ran into a case where Hibernate would auto generate a wrong database schema when two entities were mapped on the same table. The good news: it's my fault and not a bug. The better news: here's an account of how to avoid it. Let's assume a mutable entity A mapped … Continue reading ID trouble with multiple Hibernate entities on the same table →

A counterintuitive relation between CPU and memory usage

Continuing my tests on low-end server environments, I recently set up a stress test of a load balanced tomcat webapp. Part of that tests consist in reducing the available memory for the webapp (JVM -Xmx switch) and see how low it could go before negatively affecting performance. It's common knowledge that once available memory runs … Continue reading A counterintuitive relation between CPU and memory usage →

Running a java webapp in a VPS

The market is swarming with cheap Virtual Private Server (VPS) or Virtual Dedicated Server (VDS) offers [1] these days, and the specs don't look bad: you can get as much as 2GB RAM, 50GB storage space and a double core 2GHz CPU for less than 10$ / 8€ and nearly unlimited traffic. That's ideal for … Continue reading Running a java webapp in a VPS →