Steps:
1. Create Code Generation Configuration
2. Add Generic Exporter (set default values for file pattern and template name)
3. Apply/Run
4. Select Project -> Export -> Hibernate -> Ant Code Generation
5. Select file location
6. Click Finish

java.lang.NullPointerException
at org.hibernate.eclipse.launch.CodeGenXMLFactory.createRoot(CodeGenXMLFactory.java:345)
at org.hibernate.eclipse.launch.CodeGenXMLFactory.createCodeGenXML(CodeGenXMLFactory.java:471)
at org.hibernate.eclipse.codegen.ExportAntCodeGenWizardPage.getInitialContents(ExportAntCodeGenWizardPage.java:225)
at org.eclipse.ui.dialogs.WizardNewFileCreationPage.createNewFile(WizardNewFileCreationPage.java:380)
at org.hibernate.eclipse.codegen.ExportAntCodeGenWizardPage.createNewFile(ExportAntCodeGenWizardPage.java:231)
at org.hibernate.eclipse.codegen.ExportAntCodeGenWizard.performFinish(ExportAntCodeGenWizard.java:55)
at org.eclipse.jface.wizard.WizardDialog.finishPressed(WizardDialog.java:811)