由以下原因引起：org.hibernate.AnnotationException：XX上的@OneToOne或@ManyToOne引用了未知实体：YY

Question

Here my target entity which is User.class is present in a separate jar file.

package com.aa.model;
    import javax.persistence.Entity;
    import javax.persistence.JoinColumn;
    import javax.persistence.ManyToOne;
    import javax.persistence.OneToOne;

@Entity
@Table(name = "ABC")
public class Abc implements Serializable{
---    
@OneToOne(targetEntity=com.bb.model.User.class)
    @JoinColumn(name  = "CREATED_BY")
    private User createdBy;
}
---
}

The target class:

package com.bb.model;
    import java.io.Serializable;

import javax.persistence.Entity;
import javax.persistence.Table;

@Entity
@Table(name="USER")
public class User implements Serializable {
---
}

I am getting the following error:

Caused by: org.hibernate.AnnotationException: @OneToOne or @ManyToOne on com.aa.model.Abc.createdBy references an unknown entity: com.bb.model.User
    at org.hibernate.cfg.ToOneFkSecondPass.doSecondPass(ToOneFkSecondPass.java:109)
    at org.hibernate.cfg.Configuration.processEndOfQueue(Configuration.java:1598)

Answer 1

In the class Abc, you wrote

@OneToOne(targetEntity=com.bb.User.class)

instead of

@OneToOne(targetEntity=com.bb.model.User.class)

You forgot also the import of com.bb.model package

import com.bb.model.User;