Não é possível fazer a conexão JDBC

Isso pode ajudá-lo

Adicione também nome de usuário e senha

<property name="hibernate.dialect">org.hibernate.dialect.MySQLDialect</property>
   <property name="hibernate.connection.driver_class">com.mysql.jdbc.Driver</property>
   <property name="hibernate.connection.url">jdbc:mysql://localhost:3306/sampleDB</property>
   <property name="hibernate.connection.username">yourUserNameForMysql</property>
   <property name="hibernate.connection.password">passwordForMySql</property>

Após o Mysql 5.x, use a classe org.hibernate.dialect.MySQL5Dialect

<property name="hibernate.dialect">org.hibernate.dialect.MySQL5Dialect</property>
   <property name="hibernate.connection.driver_class">com.mysql.jdbc.Driver</property>
   <property name="hibernate.connection.url">jdbc:mysql://localhost:3306/sampleDB</property>
   <property name="hibernate.connection.username">yourUserNameForMysql</property>
   <property name="hibernate.connection.password">passwordForMySql</property>