alguem saber me dizer que erro é este no jpa?
NewWebService listening at address at http://localhost:8080/Ecommerce/NewWebServiceService
SEVERE: Exception while invoking class org.glassfish.persistence.jpa.JPADeployer prepare method
javax.persistence.PersistenceException: Exception [EclipseLink-28018] (Eclipse Persistence Services - 2.0.0.v20091127-r5931): org.eclipse.persistence.exceptions.EntityManagerSetupException
Exception Description: Predeployment of PersistenceUnit [EcommercePU] failed.
Internal Exception: Exception [EclipseLink-7244] (Eclipse Persistence Services - 2.0.0.v20091127-r5931): org.eclipse.persistence.exceptions.ValidationException
Exception Description: An incompatible mapping has been encountered between [class br.com.entity.SellItem] and [class br.com.entity.Sell]. This usually occurs when the cardinality of a mapping does not correspond with the cardinality of its backpointer.
at org.eclipse.persistence.internal.jpa.EntityManagerSetupImpl.predeploy(EntityManagerSetupImpl.java:986)
at org.eclipse.persistence.jpa.PersistenceProvider.createContainerEntityManagerFactory(PersistenceProvider.java:202)
at org.glassfish.persistence.jpa.PersistenceUnitLoader.loadPU(PersistenceUnitLoader.java:181)
at org.glassfish.persistence.jpa.PersistenceUnitLoader.<init>(PersistenceUnitLoader.java:96)
