Could you please help me with such case?

I have simple <Entity1>

@Entity
@Table(name="ENTITY1")
public class Entity1 {
@Id
@GeneratedValue
private Long id;

@Column(name="name")
private String name;
}

and I need without changing it (because <Entity1> is in another library) introduce many-to-many relation between the <Entity1> and <Item>.

Will it be enough just do like this:

@Entity
public class Entity2 extends Entity1 {

Set<Element> elements;

@ManyToMany(targetEntity = Element.class, fetch = FetchType.LAZY)
@JoinTable(
name = "entity1_element",
joinColumns = {@JoinColumn(name = "ent_id")},
inverseJoinColumns = {@JoinColumn(name = "elm_id")}
)
public Set<Element> getElement() {
return this.elements;
}
...

}

Or there is a better way to do it?

Thank you