Erro ao rodar o a Classe Popula Banco. | Java e JSF I: Sua aplicação web com JSF2

Estou na terceira aula deste curso, no entanto, não obtive sucesso ao rodar a classe PopulaBanco. Verifiquei que há outros tópicos sobre este tema, mas ja tentei o que foi sugerido em todos e não deu certo ainda, o erro continua o mesmo. Já troquei meu conector java para um mais recente, ja tentei a conexão com ou sem senha, e a versão da JRE já esta a 1.8 O erro impresso no console é este:

    at org.hibernate.ejb.AbstractEntityManagerImpl.convert(AbstractEntityManagerImpl.java:1377)
    at org.hibernate.ejb.AbstractEntityManagerImpl.convert(AbstractEntityManagerImpl.java:1300)
    at org.hibernate.ejb.AbstractEntityManagerImpl.throwPersistenceException(AbstractEntityManagerImpl.java:1387)
    at org.hibernate.ejb.TransactionImpl.begin(TransactionImpl.java:62)
    at br.com.caelum.livraria.dao.PopulaBanco.main(PopulaBanco.java:19)
Caused by: org.hibernate.exception.GenericJDBCException: Could not open connection
    at org.hibernate.exception.internal.StandardSQLExceptionConverter.convert(StandardSQLExceptionConverter.java:54)
    at org.hibernate.engine.jdbc.spi.SqlExceptionHelper.convert(SqlExceptionHelper.java:125)
    at org.hibernate.engine.jdbc.spi.SqlExceptionHelper.convert(SqlExceptionHelper.java:110)
    at org.hibernate.engine.jdbc.internal.LogicalConnectionImpl.obtainConnection(LogicalConnectionImpl.java:304)
    at org.hibernate.engine.jdbc.internal.LogicalConnectionImpl.getConnection(LogicalConnectionImpl.java:169)
    at org.hibernate.engine.transaction.internal.jdbc.JdbcTransaction.doBegin(JdbcTransaction.java:67)
    at org.hibernate.engine.transaction.spi.AbstractTransactionImpl.begin(AbstractTransactionImpl.java:160)
    at org.hibernate.internal.SessionImpl.beginTransaction(SessionImpl.java:1395)
    at org.hibernate.ejb.TransactionImpl.begin(TransactionImpl.java:59)
    ... 1 more
Caused by: java.sql.SQLException: The server time zone value 'Hora Padrão Brasil Central' is unrecognized or represents more than one time zone. You must configure either the server or JDBC driver (via the serverTimezone configuration property) to use a more specifc time zone value if you want to utilize time zone support.
    at com.mysql.cj.jdbc.exceptions.SQLError.createSQLException(SQLError.java:127)
    at com.mysql.cj.jdbc.exceptions.SQLError.createSQLException(SQLError.java:95)
    at com.mysql.cj.jdbc.exceptions.SQLError.createSQLException(SQLError.java:87)
    at com.mysql.cj.jdbc.exceptions.SQLError.createSQLException(SQLError.java:61)
    at com.mysql.cj.jdbc.exceptions.SQLError.createSQLException(SQLError.java:71)
    at com.mysql.cj.jdbc.exceptions.SQLExceptionsMapping.translateException(SQLExceptionsMapping.java:76)
    at com.mysql.cj.jdbc.ConnectionImpl.createNewIO(ConnectionImpl.java:862)
    at com.mysql.cj.jdbc.ConnectionImpl.<init>(ConnectionImpl.java:444)
    at com.mysql.cj.jdbc.ConnectionImpl.getInstance(ConnectionImpl.java:230)
    at com.mysql.cj.jdbc.NonRegisteringDriver.connect(NonRegisteringDriver.java:226)
    at java.sql.DriverManager.getConnection(Unknown Source)
    at java.sql.DriverManager.getConnection(Unknown Source)
    at org.hibernate.service.jdbc.connections.internal.DriverManagerConnectionProviderImpl.getConnection(DriverManagerConnectionProviderImpl.java:193)
    at org.hibernate.internal.AbstractSessionImpl$NonContextualJdbcConnectionAccess.obtainConnection(AbstractSessionImpl.java:292)
    at org.hibernate.engine.jdbc.internal.LogicalConnectionImpl.obtainConnection(LogicalConnectionImpl.java:297)
    ... 6 more
Caused by: com.mysql.cj.exceptions.InvalidConnectionAttributeException: The server time zone value 'Hora Padrão Brasil Central' is unrecognized or represents more than one time zone. You must configure either the server or JDBC driver (via the serverTimezone configuration property) to use a more specifc time zone value if you want to utilize time zone support.
    at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
    at sun.reflect.NativeConstructorAccessorImpl.newInstance(Unknown Source)
    at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(Unknown Source)
    at java.lang.reflect.Constructor.newInstance(Unknown Source)
    at com.mysql.cj.exceptions.ExceptionFactory.createException(ExceptionFactory.java:59)
    at com.mysql.cj.exceptions.ExceptionFactory.createException(ExceptionFactory.java:83)
    at com.mysql.cj.util.TimeUtil.getCanonicalTimezone(TimeUtil.java:128)
    at com.mysql.cj.protocol.a.NativeProtocol.configureTimezone(NativeProtocol.java:2201)
    at com.mysql.cj.protocol.a.NativeProtocol.initServerSession(NativeProtocol.java:2225)
    at com.mysql.cj.jdbc.ConnectionImpl.initializePropsFromServer(ConnectionImpl.java:1391)
    at com.mysql.cj.jdbc.ConnectionImpl.connectOneTryOnly(ConnectionImpl.java:993)
    at com.mysql.cj.jdbc.ConnectionImpl.createNewIO(ConnectionImpl.java:852)
    ... 14 more

Olá Léo, boa tarde!

O erro acusado na sua stack trace é este aqui:

Caused by: com.mysql.cj.exceptions.InvalidConnectionAttributeException: 
The server time zone value 'Hora Padrão Brasil Central' is unrecognized or represents more than one time zone.
You must configure either the server or JDBC driver (via the serverTimezone configuration property) to use a more 
specifc time zone value if you want to utilize time zone support.

Ou seja, o problema está no time zone . Modifique sua url de conexão, no arquivo persistence.xml, para:

<property name="javax.persistence.jdbc.url" value="jdbc:mysql://localhost/livrariadb?useTimezone=true&serverTimezone=UTC"/>

E veja se funciona. Se ainda persistir o erro, poste aqui novamente com a stack trace.