Exception "javax.persistence.EntityNotFoundException: Unable to find ParkingSpace with 3

Hi Ranchers,
Please help to find out the root cause.

I am working on oneToOne bidirectional mapping.
But while persisting the object got exception

JAVA classes.

import javax.persistence.Column;
import javax.persistence.Entity;
import javax.persistence.GeneratedValue;
import javax.persistence.GenerationType;
import javax.persistence.Id;
import javax.persistence.JoinColumn;
import javax.persistence.OneToOne;
import javax.persistence.Table;

@Entity
@Table(name="TAB_PROFESSOR")
public class Professor {
    @Id 
    @GeneratedValue(strategy=GenerationType.IDENTITY)
    private int id;
    
    @Column(name="name")
    private String name;
    
    @Column(name="salary")
    private long salary;
    
    @OneToOne 
    @JoinColumn(name="PSPACE_ID") 
    private ParkingSpace parkingSpace;

public int getId() {
        return id;
    }
    
    public void setId(int id) {
        this.id = id;
    }
    
    public String getName() {
        return name;
    }
    
    public void setName(String name) {
        this.name = name;
    }

public long getSalary() {
        return salary;
    }

public void setSalary(long salary) {
        this.salary = salary;
    }
    
    public ParkingSpace getParkingSpace() {
        return parkingSpace;
    }
    
    public void setParkingSpace(ParkingSpace parkingSpace) {
        this.parkingSpace = parkingSpace;
    }

public String toString() {
        return "Professor id: " + getId() + " name: " + getName() + 
               " with " + getParkingSpace();
    }
}

import javax.persistence.Column;
import javax.persistence.Entity;
import javax.persistence.GeneratedValue;
import javax.persistence.GenerationType;
import javax.persistence.Id;
import javax.persistence.OneToOne;
import javax.persistence.Table;

@Entity
@Table(name="TAB_PARKINGSPACE")
public class ParkingSpace {
    @Id 
    @GeneratedValue(strategy=GenerationType.IDENTITY)
    @Column(name="parkingid")
    private int id;
    
    @Column(name="lot")
    private int lot;
    
    @Column(name="location")
    private String location;
    
    @OneToOne(mappedBy="parkingSpace")
    private Professor employee;
    
    public int getId() {
        return id;
    }
    
    public void setId(int id) {
        this.id = id;
    }

public int getLot() {
        return lot;
    }

public void setLot(int lot) {
        this.lot = lot;
    }
    
    public String getLocation() {
        return location;
    }
    
    public void setLocation(String deptName) {
        this.location = deptName;
    }

public String toString() {
        return "ParkingSpace id: " + getId() + " lot: " + getLot() +
               ", location: " + getLocation();
    }

}

import javax.persistence.EntityManager;
import javax.persistence.EntityManagerFactory;
import javax.persistence.Persistence;

public class MainForOneToOneOracle {

public static void main(String[] args) {
		
		Professor professor = MainForOneToOneOracle.addProfessor();
		System.out.println("Customer id after creation:" + professor.getId());
	}
	
	/**
	 * Code to add the Professor 
	 * @param professor
	 * @return
	 */
	private static Professor addProfessor() {
		// TODO Auto-generated method stub
		EntityManagerFactory emf = Persistence
				.createEntityManagerFactory("JPAHibernate-OneToOneOracle");
		EntityManager em = emf.createEntityManager();
		em.getTransaction().begin();
		
		Professor professor = new Professor();
		professor.setId(100);
		professor.setName("Prashant Patil");
		professor.setSalary(10000);

System.out.println("Professor id before creation:" + professor.getId());

//ParkingSpce
		ParkingSpace parkingSpace = new ParkingSpace();
		parkingSpace.setId(8);
		parkingSpace.setLocation("MySpace");
		parkingSpace.setLot(1);
		
		professor.setParkingSpace(parkingSpace);

em.persist(professor);
		em.getTransaction().commit();

return professor;
	}

}

Help greatly appriciated.

Regards
PP

forgot to copy persistent.xml file

<?xml version="1.0" encoding="UTF-8"?>
<persistence version="1.0" xmlns="http://java.sun.com/xml/ns/persistence" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://java.sun.com/xml/ns/persistence http://java.sun.com/xml/ns/persistence/persistence_1_0.xsd">
	
	<persistence-unit name="JPAHibernate-OneToOneOracle" transaction-type="RESOURCE_LOCAL">
	<class>Professor</class>
	<class>ParkingSpace</class>
	<properties>
			<property name="hibernate.dialect" value="org.hibernate.dialect.Oracle9Dialect"/>
			<property name="hibernate.connection.driver_class" value="oracle.jdbc.driver.OracleDriver"/>
			<property name="hibernate.show_sql" value="true"/>
			<property name="hibernate.connection.username" value="bgadmin"/>
			<property name="hibernate.connection.password" value="bgadmin"/>
			<property name="hibernate.connection.url" value="jdbc:oracle:thin:@punapp510:1521:ATLAS"/>
			<property name="hibernate.max_fetch_depth" value="3"/>
		</properties>
	</persistence-unit>
</persistence>