@Entity
public class Student implements Serializable {

	@Id
	@GeneratedValue(strategy = GenerationType.TABLE)
	@Column(name="STUDENT_ID")
	private Long id;
        public Long getId() {
    	    return id;
        }
        public void setId(Long value) {
        	id = value; 
        }
	
        public Student() {
    	    badge = new Badge();
        }
	
	private String someField;
	public String getSomeField() {
		return someField;
	}
	public void setSomeField(String value) {
		someField = value;
	}
	
        /** The Student's badge. */
	@OneToOne(cascade={CascadeType.PERSIST, CascadeType.REMOVE, CascadeType.REFRESH})
	@JoinColumn(name="STUDENT_ID", insertable=false, updatable=false)   
	private Badge badge;
	public Badge getBadge() {
		return badge;
	}		

        PrePersist
        public void initialize() {    	
    	    badge.setStudentId(id);    	
        }	
}

@Entity
public class Badge implements Serializable {
	
	
	@Id
	@Column(name="STUDENT_ID")	    
	private Long studentId;    
	public Long getStudentId() {
		return studentId;
	}	
	public void setStudentId(Long value) {
		studentId = value;
	}

	
	
        @Column(name = "SECURITY_LEVEL")
        private Long mSecurityLevel;
        public Long getSecurityLevel() {
        	return mSecurityLevel;
        }
        public void setSecurityLevel(Long value) {
        	mSecurityLevel = value;
        }    
}