Не могу понять что почем

package entity;
 
import java.io.Serializable;
import javax.persistence.CascadeType;
import javax.persistence.Entity;
import javax.persistence.GeneratedValue;
import javax.persistence.GenerationType;
import javax.persistence.Id;
import javax.persistence.ManyToOne;
 
/**
 *
 * @author механик
 */
@Entity
public class Student implements Serializable{
  @Id
  @GeneratedValue(strategy=GenerationType.AUTO)
    private int studentId;
  
    private String studentName;
    private String studentSurname;
    private String studentFathername;
    
    @ManyToOne(cascade = CascadeType.ALL)
    private Status status_statusId;
 
    public int getStudentId() {
        return studentId;
    }
    public void setStudentId(int studentId) {
        this.studentId = studentId;
    }
      
 
    public String getStudentName() {
        return studentName;
    }
    public void setStudentName(String studentName) {
        this.studentName = studentName;
    }
    
 
    public String getStudentSurname() {
        return studentSurname;
    }
    public void setStudentSurname(String studentSurname) {
        this.studentSurname = studentSurname;
    }
    
 
    public String getStudentFathername() {
        return studentFathername;
    }
    public void setStudentFathername(String studentFathername) {
        this.studentFathername = studentFathername;
    }
    
 
    public Status getStatus_statusId() {
        return status_statusId;
    }
    public void setStatus_statusId(Status status_statusId) {
        this.status_statusId = status_statusId;
    }
 
}

package entity;
 
import java.io.Serializable;
import javax.persistence.Entity;
import javax.persistence.GeneratedValue;
import javax.persistence.GenerationType;
import javax.persistence.Id;
 
/**
 *
 * @author механик
 */
@Entity
public class Grupa implements Serializable{
   @Id
   @GeneratedValue(strategy=GenerationType.AUTO)
    private int grupaId;
 
    public int getGrupaId() {
        return grupaId;
    }
 
    public void setGrupaId(int grupaId) {
        this.grupaId = grupaId;
    }
     private String nameGrupa;
 
    public String getNameGrupa() {
        return nameGrupa;
    }
 
    public void setNameGrupa(String nameGrupa) {
        this.nameGrupa = nameGrupa;
    }
    private int kurs;
 
    public int getKurs() {
        return kurs;
    }
 
    public void setKurs(int kurs) {
        this.kurs = kurs;
    }
    private int specialnost_specialnostId;
 
    public int getSpecialnost_specialnostId() {
        return specialnost_specialnostId;
    }
 
    public void setSpecialnost_specialnostId(int specialnost_specialnostId) {
        this.specialnost_specialnostId = specialnost_specialnostId;
    }
    private int formObuch_formObuchId;
 
    public int getFormObuch_formObuchId() {
        return formObuch_formObuchId;
    }
 
    public void setFormObuch_formObuchId(int formObuch_formObuchId) {
        this.formObuch_formObuchId = formObuch_formObuchId;
    }
 
}