How to do REST POST request validation for ID - (Entity ID should be null in this case even if they inject in request)

Question

How to validate the below situation,

Entity:

@Entity
@Table
public class Idea {
  @Id
  @GeneratedValue(strategy = GenerationType.AUTO)
  private long id;

  @Column
  @Size(min=1,max=10)
  private String title;
}

POST REQ: (Valid Input) - Properly inserts the data

{ "title":"sample" }

POST REQ: (InValid Input) - Trying to update the data for the ID in POST

{ "id":1, "title":"sample" }

How to validate the above situation when only on post request happens then the input should have a non ID field or id field with null? like @Null or @NotNull validations.

Note: I have to use the same entity for GET/PUT(should allow id value) as well