SQL

java.sql.sqlexception: access denied for user

You have to grant priviliges to root@localhost
e.g 
GRANT ALL PRIVILIGES ON *.* TO 'root'@'localhost' IDENTIFIED BY password

(*.*: means everything, it can be modified to some specific DB or opertations)

java.sql.sqlexception: access denied for user

You can flush the root user's priviliges in mysql cli.

> ALTER USER 'root'@'localhost' IDENTIFIED WITH mysql_native_password BY 'password';
> FLUSH PRIVILEGES;

java.sql.sqlexception: access denied for user

As you are creating a database from scratch, you could use:

Connection connection = DriverManager.getConnection("jdbc:mysql://localhost/?user=root&password=rootpassword"); 
PreparedStatement ps = connection.prepareStatement("CREATE DATABASE databasename");
int result = ps.executeUpdate();