PersistenceIT random failures

java.lang.NoClassDefFoundError: Could not initialize class org.infinispan.server.persistence.PersistenceIT

The reason for the error is that PersistenceIT has a static final field InfinispanServerRule SERVERS, and the InfinispanServerRule constructor may throw an exception. The first time the JVM tries to initialize the PersistenceIT class, the caller gets an ExceptionInInitializerError, but further attempts get the NoClassDefFoundError instead. And since this is all inside Surefire/JUnit, the initial ExceptionInInitializerError is ignored somewhere without being logged.

To help debugging via logs, the constructor should be trivial, and the serverDriver should only be initialized in the apply() method.