OpenJPA creates a separate table for collection attributes that are annotated with org.apache.openjpa.persistence.PersistentCollection. To have the same behavior in EclipseLink, replace these annotations with the @ElementCollection and @Column annotations as defined in the JPA specification. If you remove the @PersistentCollection annotation and do not add the @ElementCollection and @Column annotations, EclipseLink treats the field as a BLOB and tries to create a column for the data in the entity's table.

This rule scans for org.apache.openjpa.persistence.PersistentCollection annotations so that you can manually migrate them. To migrate the annotations, perform the following steps:

1. Replace the @org.apache.openjpa.persistence.PersistentCollection annotation with

   @javax.persistence.ElementCollection
   @javax.persistence.Column(name="element")
   

   If there is already a @Column annotation on the attribute, do not add another one or change the name.
2. Change arrays to collections of objects. Use primitive wrapper types instead of primitives.

For example, this rule flags the @PersistentCollection annotation in the following entity class:

import javax.persistence.Entity;
import javax.persistence.Id;
import org.apache.openjpa.persistence.PersistentCollection;

@Entity
public class IntArrayEntity{
    @Id
    private int id;
    
    @PersistentCollection
    private int[] arrayOfInts;

}

To migrate this entity, replace the annotation and change the int array to a list of Integer objects: List<Integer>.

import javax.persistence.Column;
import javax.persistence.ElementCollection;
import javax.persistence.Entity;
import javax.persistence.Id;

@Entity
public class IntArrayEntity{
    @Id
    private int id;
    
    @ElementCollection
    @Column(name="element")
    private List<Integer> arrayOfInts;
}

For information about this OpenJPA to EclipseLink migration issue, see the Migration from OpenJPA to EclipseLink JPA: Extended Functionality guide.