java.lang.NullPointerException
   at org.netbeans.modules.j2ee.jpa.refactoring.rename.PersistenceXmlPackageRename.prepare(PersistenceXmlPackageRename.java:99)
   at org.netbeans.modules.j2ee.jpa.refactoring.JPARefactoringPlugin.prepare(JPARefactoringPlugin.java:89)
   at org.netbeans.modules.refactoring.api.AbstractRefactoring.pluginsPrepare2(AbstractRefactoring.java:419)
   at org.netbeans.modules.refactoring.api.AbstractRefactoring.pluginsPrepare(AbstractRefactoring.java:403)
   at org.netbeans.modules.refactoring.api.AbstractRefactoring.prepare(AbstractRefactoring.java:214)
   at org.netbeans.modules.refactoring.spi.impl.ParametersPanel$Prepare.run(ParametersPanel.java:803)
   at org.openide.util.RequestProcessor$Task.run(RequestProcessor.java:1356)
   at org.openide.util.RequestProcessor$Processor.run(RequestProcessor.java:1894)