HikariConfig configuration = new HikariConfig();
    configuration.setJdbcUrl("jdbc:mysql://127.0.0.1:3306/testdb");
    configuration.addDataSourceProperty("serverName","127.0.0.1");
    configuration.addDataSourceProperty("port", 3306);
    configuration.addDataSourceProperty("databaseName", "testdb"));
    configuration.addDataSourceProperty("user", "root");
    configuration.addDataSourceProperty("password", "123");
    configuration.setDriverClassName("com.mysql.jdbc.jdbc2.optional.MysqlDataSource");
    this.database = new HikariDataSource(configuration);
    return true;

[main] INFO com.zaxxer.hikari.HikariDataSource - HikariPool-0 - is starting.
[main] WARN com.zaxxer.hikari.util.DriverDataSource - Registered driver with driverClassName=org.mariadb.jdbc.MySQLDataSource was not found, trying direct instantiation.
[main] WARN com.zaxxer.hikari.util.DriverDataSource - Could not instantiate instance of driver class org.mariadb.jdbc.MySQLDataSource, trying JDBC URL resolution
java.lang.ClassCastException: org.mariadb.jdbc.MySQLDataSource cannot be cast to java.sql.Driver