Close a Frame when another one opened

Question

How do i Close a frame (dependent Frame) when another frame opened
dispose() method did nothing and so do system.exit(0); as the System.exit(0) close the whole app that meant also the frame i would like to open when the other frame closed and moved from " Memory " huge topic for me
dispose(); didn't do what i really needed to happened
please any suggestions ASAP ? i need that in swing app

Answer 1

i used dispose() but didn't work with me as i noticed the memory usage with this java app when i run the app after closing the frame . the memory usage didn't change that meant as least the frame didn't closed or cleared from the memory ?!
        try {
                Socket ss = new Socket("14.23.5.122", 1235);
              //  JOptionPane.showMessageDialog(null, "Server's OK", "Connection", JOptionPane.INFORMATION_MESSAGE);
                new LoginFrame().setVisible(true);
              //  this.dispose();
                this.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
            } catch (UnknownHostException eh) {
                System.out.println("Unknow Host Exception"+ eh.getMessage());
            } catch (IOException eo) {
                System.exit(0);
               System.out.println("IO Exception"+ eo.getMessage());
         /*finally{
        System.exit(0);
        }*/