Org.hibernate.AnnotationException:No identifier specified for entity

caused by:org.hibernate.AnnotationException:No identifier specified for entity:

When you use Hibernate's e-r to map the Pojo class, you encounter a org.hibernate.AnnotationException:No identifier specified for entity exception. However, the entity class comment is not a problem, the only thing that is not normal is that this table is more special without a primary key , as if the entity class must be primary key when using Hibernate's mapping table. Otherwise, the exception will be reported.
The solution is to add a primary key to go in, adding the primary key to the artifact in my previous article, here is mainly on the entity class comments, should do to add
@Id
@GeneratedValue (strategy=generationtype.identity)
@Column (name = "id", nullable = false)
Private int ID;

Org.hibernate.AnnotationException:No identifier specified for entity