In OpenJPA, when a relationship attribute has either a @OneToOne or a @ManyToOne annotation with a @Column annotation, the @Column annotation is treated as a @JoinColumn annotation. EclipseLink throws an exception that indicates that the entity class must use @JoinColumn instead of @Column to map a relationship attribute.

This rule flags @Column annotations that are used with OneToOne or ManyToOne annotations. An automated fix will replace the @Column annotation with a @JoinColumn annotation. All corresponding annotation attributes are copied to the @JoinColumn annotation. The javax.persistence.Column elements length, precision, and scale are not copied.

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

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

@Entity
public class TransactionEntity {
    @Id
    private int id;
 
    private long transactionNumber;
    private double amount;
    
    @ManyToOne
    @Column(name="account")
    private Account account;
}

An automated fix will replace the @Column annotation with a @JoinColumn annotation and provides the appropriate imports.

import javax.persistence.Entity;
import javax.persistence.Id;
import javax.persistence.ManyToOne;
import javax.persistence.JoinColumn;

@Entity
public class TransactionEntity {
    @Id
    private int id;
 
    private long transactionNumber;
    private double amount;
    
    @ManyToOne
    @JoinColumn(name="account")
    private Account account;
}

For information about this issue and other OpenJPA to EclipseLink migration issues, see the OpenJPA to EclipseLink JPA Migration: Mappings guide.