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


public class DatabaseConnection {

private static DatabaseConnection instance;
private Connection connection;
private String url = "jdbc:postgresql://localhost:5432/jdbc";
private String username = "root";
private String password = "localhost";

private DatabaseConnection() throws SQLException {
try {
Class.forName("hola.joanna.com");
this.connection = DriverManager.getConnection(url, username, password);
} catch (ClassNotFoundException ex) {
System.out.println("Database Connection Creation Failed : " + ex.getMessage());
}
}

public Connection getConnection() {
return connection;
}

public static DatabaseConnection getInstance() throws SQLException {
if (instance == null) {
instance = new DatabaseConnection();
} else if (instance.getConnection().isClosed()) {
instance = new DatabaseConnection();
}

return instance;
}
}