Exception in thread

deu pau

set 08, 2020 11:18:26 AM org.hibernate.jpa.internal.util.LogHelper logPersistenceUnitInformation
INFO: HHH000204: Processing PersistenceUnitInfo [name: contas]
set 08, 2020 11:18:26 AM org.hibernate.Version logVersion
INFO: HHH000412: Hibernate ORM core version 5.4.21.Final
set 08, 2020 11:18:26 AM org.hibernate.annotations.common.reflection.java.JavaReflectionManager <clinit>
INFO: HCANN000001: Hibernate Commons Annotations {5.1.0.Final}
set 08, 2020 11:18:26 AM org.hibernate.engine.jdbc.connections.internal.DriverManagerConnectionProviderImpl configure
WARN: HHH10001002: Using Hibernate built-in connection pool (not for production use!)
Loading class `com.mysql.jdbc.Driver'. This is deprecated. The new driver class is `com.mysql.cj.jdbc.Driver'. The driver is automatically registered via the SPI and manual loading of the driver class is generally unnecessary.
set 08, 2020 11:18:26 AM org.hibernate.engine.jdbc.connections.internal.DriverManagerConnectionProviderImpl buildCreator
INFO: HHH10001005: using driver [com.mysql.jdbc.Driver] at URL [jdbc:mysql://localhost/alura_jpa]
set 08, 2020 11:18:26 AM org.hibernate.engine.jdbc.connections.internal.DriverManagerConnectionProviderImpl buildCreator
INFO: HHH10001001: Connection properties: {user=root, password=****}
set 08, 2020 11:18:26 AM org.hibernate.engine.jdbc.connections.internal.DriverManagerConnectionProviderImpl buildCreator
INFO: HHH10001003: Autocommit mode: false
set 08, 2020 11:18:26 AM org.hibernate.engine.jdbc.connections.internal.DriverManagerConnectionProviderImpl$PooledConnections <init>
INFO: HHH000115: Hibernate connection pool size: 20 (min=1)
set 08, 2020 11:18:27 AM org.hibernate.dialect.Dialect <init>
INFO: HHH000400: Using dialect: org.hibernate.dialect.MySQL5InnoDBDialect
Exception in thread "main" org.hibernate.AnnotationException: No identifier specified for entity: br.com.alura.jpa.modelo.Conta
    at org.hibernate.cfg.InheritanceState.determineDefaultAccessType(InheritanceState.java:266)
    at org.hibernate.cfg.InheritanceState.getElementsToProcess(InheritanceState.java:211)
    at org.hibernate.cfg.AnnotationBinder.bindClass(AnnotationBinder.java:779)
    at org.hibernate.boot.model.source.internal.annotations.AnnotationMetadataSourceProcessorImpl.processEntityHierarchies(AnnotationMetadataSourceProcessorImpl.java:254)
    at org.hibernate.boot.model.process.spi.MetadataBuildingProcess$1.processEntityHierarchies(MetadataBuildingProcess.java:230)
    at org.hibernate.boot.model.process.spi.MetadataBuildingProcess.complete(MetadataBuildingProcess.java:273)
    at org.hibernate.jpa.boot.internal.EntityManagerFactoryBuilderImpl.metadata(EntityManagerFactoryBuilderImpl.java:1224)
    at org.hibernate.jpa.boot.internal.EntityManagerFactoryBuilderImpl.build(EntityManagerFactoryBuilderImpl.java:1255)
    at org.hibernate.jpa.HibernatePersistenceProvider.createEntityManagerFactory(HibernatePersistenceProvider.java:56)
    at javax.persistence.Persistence.createEntityManagerFactory(Persistence.java:79)
    at javax.persistence.Persistence.createEntityManagerFactory(Persistence.java:54)
    at br.com.alura.jpa.testes.TesteCriaTabelas.main(TesteCriaTabelas.java:10)

Henrique, sua classe Conta dentro do pacote modelo está desse jeito? Inclusive com a anotação @Id e respectivos imports?

package br.com.alura.jpa.modelo;

import javax.persistence.Entity;
import javax.persistence.GeneratedValue;
import javax.persistence.GenerationType;
import javax.persistence.Id;

@Entity
public class Conta {
    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    private Long id;
    private Integer agencia;
    private Integer numero;
    private String titular;

    public Long getId() {
        return id;
    }

    public void setId(Long id) {
        this.id = id;
    }

    public Integer getAgencia() {
        return agencia;
    }

    public void setAgencia(Integer agencia) {
        this.agencia = agencia;
    }

    public Integer getNumero() {
        return numero;
    }

    public void setNumero(Integer numero) {
        this.numero = numero;
    }

    public String getTitular() {
        return titular;
    }

    public void setTitular(String titular) {
        this.titular = titular;
    }

}