jdbc error getting response for myTeststep; null

Oh, I missed to show my sql-query in Ready-API, but it is the same as in the java code.

import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;

public class Test {

	public static void main(String[] args) throws InstantiationException, IllegalAccessException, ClassNotFoundException, SQLException {
		
	String url = "jdbc:cassandra://localhost:9042/mykeyspace?user=myusername&password=mypassword";
	       
        DriverManager.getDriver(url);
        Connection con = DriverManager.getConnection(url);
        
        Statement stmt = con.createStatement();
        ResultSet rs = stmt.executeQuery("select * from mykeyspace.mytable limit 5;");

        while (rs.next())
        	System.out.println(rs.getString(1));        
        
        rs.close();
        stmt.close();
        con.close();

	}
}