First off, what is this file all about?
com.genuitec.eclipse.persistence.jpa.prefs
Periodically my Spring container will fail to start with a message that a persistence unit could not be found. Understand I get this message only a few minutes following a successful server start! When I look in the generated (add JPA support) META-INF folder I notice the persistence.xml has lost is pretty iconic decoration and looks like any old XML file. Each time I detect this I right-click project -> properties -> ME -> Java Persistence to find the link telling me I have no persistence file! I click through the wizard and the graphics are reapplied to the folder icon.