Erro de Exception in thread "main" que não consigo resolver

Procurei em todos os tópicos e não achei nenhuma exception igual a essa:

Exception in thread "main" javax.persistence.PersistenceException: org.hibernate.PersistentObjectException: detached entity passed to persist: br.com.alura.loja.modelo.Produto at org.hibernate.internal.ExceptionConverterImpl.convert(ExceptionConverterImpl.java:154) at org.hibernate.internal.ExceptionConverterImpl.convert(ExceptionConverterImpl.java:181) at org.hibernate.internal.ExceptionConverterImpl.convert(ExceptionConverterImpl.java:188) at org.hibernate.internal.SessionImpl.firePersist(SessionImpl.java:726) at org.hibernate.internal.SessionImpl.persist(SessionImpl.java:706) at br.com.alura.loja.testes.CadastroDeProdutos.main(CadastroDeProdutos.java:24) Caused by: org.hibernate.PersistentObjectException: detached entity passed to persist: br.com.alura.loja.modelo.Produto at org.hibernate.event.internal.DefaultPersistEventListener.onPersist(DefaultPersistEventListener.java:120) at org.hibernate.event.internal.DefaultPersistEventListener.onPersist(DefaultPersistEventListener.java:55) at org.hibernate.event.service.internal.EventListenerGroupImpl.fireEventOnEachListener(EventListenerGroupImpl.java:102) at org.hibernate.internal.SessionImpl.firePersist(SessionImpl.java:720) ... 2 more

<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 https://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>
    <groupId>br.com.alura</groupId>
    <artifactId>loja</artifactId>
    <version>0.0.1-SNAPSHOT</version>

    <build>
        <plugins>
            <plugin>
                <groupId>org.apache.maven.plugins</groupId>
                <artifactId>maven-compiler-plugin</artifactId>
                <version>3.8.0</version>
                <configuration>
                    <release>11</release>
                </configuration>
            </plugin>
        </plugins>
    </build>

    <dependencies>
        <dependency>
            
            <groupId>org.hibernate</groupId>
            <artifactId>hibernate-entitymanager</artifactId>
            <version>5.4.27.Final</version>
        
        </dependency>

        <dependency>
            <groupId>com.oracle.database.jdbc</groupId>
            <artifactId>ojdbc11</artifactId>
            <version>23.2.0.0</version>
        </dependency>
    </dependencies>
</project>

<?xml version="1.0" encoding="UTF-8"?>

<persistence version="2.2"
    xmlns="http://xmlns.jcp.org/xml/ns/persistence"
    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xsi:schemaLocation="http://xmlns.jcp.org/xml/ns/persistence http://xmlns.jcp.org/xml/ns/persistence/persistence_2_2.xsd">

    <persistence-unit name="loja" transaction-type="RESOURCE_LOCAL">
        <properties>
            <property name="javax.persistence.jdbc.driver" value="oracle.jdbc.OracleDriver" />
            <property name="javax.persistence.jdbc.url" value="jdbc:oracle:thin:@localhost:1521:xe"/>
            <property name="javax.persistence.jdbc.user" value="system"/>
            <property name="javax.persistence.jdbc.password" value="LuOracle@44"/>

            <property name="hibernate.dialect" value="org.hibernate.dialect.Oracle8iDialect" />
            <property name="hibernate.show_sql" value="true"/>
            <property name="hibernate.hbm2ddl.auto" value="update"/>
        </properties>
    </persistence-unit>
</persistence>

Desconfio que haja algo de errado com essa classe, tentei mudar essa anotação, mas nada alterou.

package br.com.alura.loja.modelo;
import java.math.BigDecimal;
import javax.persistence.Entity;
import javax.persistence.GeneratedValue;
import javax.persistence.GenerationType;
import javax.persistence.Id;
import javax.persistence.Table;

@Entity
@Table(name = "produtos")
public class Produto {

    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    private Long id;
    private String nome;
    private String descricao;
    private BigDecimal preco;

    //retirei geters e seters para não ultrapassar os caracteres permitidos...
}

package br.com.alura.loja.testes;

import java.math.BigDecimal;

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

import br.com.alura.loja.modelo.Produto;

public class CadastroDeProdutos {
    public static void main(String[] args) {
        Produto celular = new Produto();
        celular.setId(4598623l);
        celular.setNome("Xiaomi Redmi");
        celular.setDescricao("Muito legal");
        celular.setPreco(new BigDecimal("800"));

        EntityManagerFactory factory = Persistence.createEntityManagerFactory("loja");

        EntityManager em = factory.createEntityManager();

        em.getTransaction().begin();
        em.persist(celular);
        em.getTransaction().commit();
        em.close();

    }

}