Hi,

assume we have:

@Entity
public class Template {
...
    @OneToOne(mappedBy="template", cascade = ALL)
    private Document document;
    public Document getDocument() {
        return document;
    }
    public void setDocument(Document document) {
        this.document = document;
    }
...
}

and

@Entity
public class Document {
...
    @OneToOne(cascade = ALL)
    private Template template;
    public Template getTemplate() {
        return template;
    }
    public void setTemplate(Template template) {
        this.template = template;
    }
...
}

Now we write the code

Document d = new Document();
Template t = new Template();
d.setTemplate(t);

Before persisting:
d.getTemplate() gives t
but
t.getDocument() gives null.

This is quite OK.

After persisting and then fetching (fd is fetched Document):
fd.getTemplate() gives t
but
fd.getTemplate().getDocument() gives null :/.

Is it a good idea to change the above method to
public void setTemplate(Template template) {
    this.template = template;
    template.setDocument(this);
}
public void setDocument(Document document) {
    this.document = document;
    document.setTemplate(this);
}

?