Add null check to close listener

diff --git a/grails-datastore-gorm-hibernate5/src/main/groovy/org/grails/orm/hibernate/cfg/HibernateMappingContextConfiguration.java b/grails-datastore-gorm-hibernate5/src/main/groovy/org/grails/orm/hibernate/cfg/HibernateMappingContextConfiguration.java
index 3ea9076..0dfb973 100644
--- a/grails-datastore-gorm-hibernate5/src/main/groovy/org/grails/orm/hibernate/cfg/HibernateMappingContextConfiguration.java
+++ b/grails-datastore-gorm-hibernate5/src/main/groovy/org/grails/orm/hibernate/cfg/HibernateMappingContextConfiguration.java

@@ -269,7 +269,9 @@
             private static final long serialVersionUID = 1;
             public void sessionFactoryCreated(SessionFactory factory) {}
             public void sessionFactoryClosed(SessionFactory factory) {
-                ((ServiceRegistryImplementor)serviceRegistry).destroy();
+                if (serviceRegistry != null) {
+                    ((ServiceRegistryImplementor)serviceRegistry).destroy();
+                }
             }
         });