Hi Juan, As you've discovered, adding/removing relationships require the Cayenne objects to be registered in an ObjectContext (typically a DataContext). Generally you'll create and register your objects in an OC using:
DocumentoInventario documentoInventario = objectContext.newObject( DocumentoInventario.class); although you can register them separately: DocumentoInventario documentoInventario = new DocumentoInventario(); objectContext.registerNewObject(documentoInventario); mrg On Fri, Apr 8, 2016 at 7:30 PM, Juan Manuel Diaz Lara < jmdia...@yahoo.com.invalid> wrote: > I am using Cayenne 4.0.M3. > I want to build an graph of persistent objects using the api for many > targets, but I get the following trace: > Exception in thread "main" java.lang.NullPointerException > at > org.apache.cayenne.CayenneDataObject.addToManyTarget(CayenneDataObject.java:248) > at > com.ace.pcexpress.pos.model.auto._DocumentoInventario.addToDetalle(_DocumentoInventario.java:92) > at > org.example.cayenne.Main.setupNewDocumentoInventarioWithNewProduct(Main.java:350) > at org.example.cayenne.Main.main(Main.java:80) > Which relevan line on cayenne code is: > getObjectContext().propertyChanged(this, relName, null, value); > this fails because the source object is transient (so, does not have an > objectcontex). The same happens with removeToManyTarget. Atte. Juan Manuel > Díaz Lara
