public static void main(String[] args) throws Exception {
        String[] dbInfo = {"jdbc:postgresql:my_database", "postgres", "fakepassword"};
        if(args != null && ArrayUtils.contains(args, "mysql"))  {
            dbInfo = new String[]{"jdbc:mysql://localhost:3306/my_database", "mysql", "fakepassword"};
        }
        System.out.println("Trying to connect to: " + dbInfo[0]);

        Connection con = DriverManager.getConnection(dbInfo[0], dbInfo[1], dbInfo[2]);
        PreparedStatement ps = con.prepareStatement("select * from courses"); 
        ResultSet rs = ps.executeQuery();
        while (rs.next()) {
            System.out.println("id: " + rs.getInt("id") + ", code: " + rs.getString("code") + ", description: "
                    + rs.getString("description"));
        }

        con.close();
        // postresql is not closing resultset or preparedstatement upon con closing!!!
        // postresql:   con closed? true, ps closed? false, rs closed? false
        // mysql:       con closed? true, ps closed? true, rs closed? true
        System.out.println("con closed? " + con.isClosed() + ", ps closed? " + ps.isClosed() 
            + ", rs closed? " + rs.isClosed());
    }

import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.ResultSet;
import java.sql.Statement;
import java.util.Properties;

public class TestNullsFirst {
    public static void main(String []args) throws Exception {


        String url = "jdbc:postgresql://localhost:5432/test";

        Properties props = new Properties();
        props.setProperty("user", "test");
        props.setProperty("password", "test");
        try ( Connection conn = DriverManager.getConnection(url, props) ){
            try ( Statement statement = conn.createStatement() ) {
                try (ResultSet rs = statement.executeQuery( "select lastname from users order by lastname asc nulls first") ){
                    if (rs.next())
                        System.out.println( "Get String: " + rs.getString(1));
                }
            }
        }
    }
}