'java.lang.NullPointerException' while persisting an entity with an associated null embeddable in Hibernate

Issue

• An entity is defined with an optional association with an embeddable which has a @PreUpdate annotated method.

• When persisting an entity with a null embeddable, a NullPointerException is raised:

  ... java.lang.RuntimeException: java.lang.NullPointerException
      at org.hibernate.jpa.event.internal.EmbeddableCallback.performCallback(EmbeddableCallback.java:48)
      at org.hibernate.jpa.event.internal.CallbackRegistryImpl.callback(CallbackRegistryImpl.java:97)
      at org.hibernate.jpa.event.internal.CallbackRegistryImpl.preCreate(CallbackRegistryImpl.java:57)
      at org.hibernate.event.internal.AbstractSaveEventListener.saveWithGeneratedId(AbstractSaveEventListener.java:112)
      at org.hibernate.event.internal.DefaultPersistEventListener.entityIsTransient(DefaultPersistEventListener.java:192)
      at org.hibernate.event.internal.DefaultPersistEventListener.onPersist(DefaultPersistEventListener.java:135)
      ...