When scala unitests won’t run in the Scala IDE with Maven

Stupid problem: scala unit tests / scalatest tests suddenly won't run after a failed maven build claiming with a ClassNotFoundException that the test class doesn't exist. I believe this to be a weird class loading issue where Eclipse doesn't include unit tests into the classpath. The very, very sad workaround is: run a successful maven … Continue reading When scala unitests won’t run in the Scala IDE with Maven →

LocalContainerEntityManagerFactoryBean, Hibernate and superflous tables created in wrong database

TL;DR Hibernate's (3.2-3.4) JPA implementation will pick up hbm files on it's own when it should be looking only at persistence.xml, thus: - loading more entities that it should - loading the wrong entities - performing schema updates in the wrong database This one annoyed me plenty and took a great deal of debugging to … Continue reading LocalContainerEntityManagerFactoryBean, Hibernate and superflous tables created in wrong database →

java.lang.NoClassDefFoundError: org/apache/openjpa/enhance/PersistenceCapable

My current project is using JPA, heavily. JPA is a spec/standard/interface and I'm using the Hibernate implementation for it, but I import the entities from a different maven module. The entities module has a dependency on JPA, but not on Hibernate. So when I run my unit tests, I suddenly get a: java.lang.NoClassDefFoundError: org/apache/openjpa/enhance/PersistenceCapable Openjpa? … Continue reading java.lang.NoClassDefFoundError: org/apache/openjpa/enhance/PersistenceCapable →

An easier to use Java REST client

I recently was duped (by myself) at a discussion with a colleague: in our continuous effort to disentangle release schedules of two tightly entangled applications, I exposed some core features as a JSON REST service and told him to "just use the Spring invoker" for JSON. It turns out, there is one for JaxRS, Burlap, … Continue reading An easier to use Java REST client →

On JPA identifiers and business keys (or why business keys are a bad idea)

JPA, and for that matter Hibernate, depends on identifying entity instances (I'll refer to them as entities for short) by some key. That key can either be a single property (like a numeric ID column in the corresponding table) or a business key (also referred to as natural key). Business keys are entity properties which … Continue reading On JPA identifiers and business keys (or why business keys are a bad idea) →