[RESOLVED] how to disconnect to database in this case?

[Emerald214]

I'm working with JDBC.

1) I want to disconnect to database in a destructor because my class uses the connection during execution time. Please give me a hand where I should put my disconnectToDatabase() method.

2) I googled for that and I used finalize() method but when I closed my frame, it didn't show the message dialog. I think there is memory leak.
So in fact, when is finalize() method invoked? How to disconnect to database in this case?

public class LeftPane extends JPanel
{
        private DatabaseLoader databaseLoader;
	
        public LeftPane()
        {
                try {
			databaseLoader = new DatabaseLoader();			
		} catch (ClassNotFoundException e) {
			System.err.println("Have no a driver");
		}

                ...

                // connect to database
		try {
			databaseLoader.connectToDatabase();		
			...
		} catch (SQLException e) {
			System.err.println("Database error");
		}
                ...
         }

         protected void finalize() throws Throwable 
	{		
		JOptionPane.showMessageDialog(null, "End"); // it doesn't show when I close my app.

                // disconnect to database
		databaseLoader.disconnectToDatabase();
		super.finalize();
	};
}

Thank you.