import java.net.MalformedURLException;
import java.net.URL;
import java.net.URLClassLoader;
import java.sql.*;
import java.util.Properties;

public class PrintPg {
    static String url = "jdbc:postgresql://localhost:5432/postgres";
    static String pgJarPath = "file:/path/to/postgresql-9.4.1208.jar";

    public static void main(String[] args) throws SQLException, ClassNotFoundException, IllegalAccessException, InstantiationException, MalformedURLException {

        URLClassLoader child = new URLClassLoader(new URL[] { new URL(pgJarPath) }, PrintPg.class.getClassLoader());
        Class<?> driverClass = Class.forName("org.postgresql.Driver", true, child);
        Driver driver = (Driver) driverClass.newInstance();

        Properties info = new Properties();
        info.setProperty("user", "postgres");
        info.setProperty("password", "postgres");
        Connection c = driver.connect(url, info);

        c.setAutoCommit(true);
        PreparedStatement stmt = c.prepareStatement("SELECT * FROM information_schema.columns");
        ResultSet rs = stmt.executeQuery();

        while (rs.next()) {
            System.out.println(""
                    + rs.getString("table_catalog") + "\t"
                    + rs.getString("table_schema") + "\t"
                    + rs.getString("table_name") + "\t"
                    + rs.getString("column_name") + "\t"
                    + rs.getLong("ordinal_position")
            );
        }

        rs.close();
        c.close();
    }
}