SqlEjemplo.java

import java.sql.*;

class SqlEjemplo {
    public static void main(String[] args) throws Exception {
        System.out.println("Hello world!");
        // instalar la libreria 
        // https://mvnrepository.com/artifact/org.postgresql/postgresql/42.2.9
        String user = "vxgdibal";
        String password = "jGBKv3F7IVEaUzA6ajoWY8sXQWyLD9z9";
        String url = "jdbc:postgresql://manny.db.elephantsql.com:5432/vxgdibal";
        try (Connection conn = DriverManager.getConnection(url, user, password)) {
            PreparedStatement preparedStatement = conn.prepareStatement("SELECT id, nombre from cliente");

            ResultSet resultSet = preparedStatement.executeQuery();

            while (resultSet.next()) {

                int id = resultSet.getInt("ID");
                String nombre = resultSet.getString("nombre");
                System.out.println(String.format("Cliente id=%s nombre=%s", id, nombre));
            }
        } catch (SQLException e) {
            System.err.format("SQL State: %s\n%s", e.getSQLState(), e.getMessage());
        } catch (Exception e) {
            e.printStackTrace();
        }

    }
}