IllegalArgumentException: Expecting collection type ... in Hibernate 4

Issue

• Declaring an @ ElementCollection as below

      @ElementCollection
      @IndexColumn(name = "idx")
      private String[] strings;
  

• Creation of the EntityManager fails with

  java.lang.IllegalArgumentException: Expecting collection type [[Ljava.lang.String;]
      at org.hibernate.ejb.metamodel.AttributeFactory.determineCollectionType(AttributeFactory.java:902)
      at org.hibernate.ejb.metamodel.AttributeFactory$PluralAttributeMetadataImpl.(AttributeFactory.java:756)
      at org.hibernate.ejb.metamodel.AttributeFactory$PluralAttributeMetadataImpl.(AttributeFactory.java:737)
      at org.hibernate.ejb.metamodel.AttributeFactory.determineAttributeMetadata(AttributeFactory.java:520)
      at org.hibernate.ejb.metamodel.AttributeFactory.buildAttribute(AttributeFactory.java:100)
      at org.hibernate.ejb.metamodel.MetadataContext.wrapUp(MetadataContext.java:207)
      at org.hibernate.ejb.metamodel.MetamodelImpl.buildMetamodel(MetamodelImpl.java:83)
      at org.hibernate.ejb.EntityManagerFactoryImpl.(EntityManagerFactoryImpl.java:106)
      at org.hibernate.ejb.Ejb3Configuration.buildEntityManagerFactory(Ejb3Configuration.java:915)
      at org.hibernate.ejb.Ejb3Configuration.buildEntityManagerFactory(Ejb3Configuration.java:900)
      at org.hibernate.ejb.HibernatePersistence.createEntityManagerFactory(HibernatePersistence.java:59)
      at javax.persistence.Persistence.createEntityManagerFactory(Persistence.java:63)
      at javax.persistence.Persistence.createEntityManagerFactory(Persistence.java:47)
      ...