How to Run application in background when close the JFrame?

I used a system tray in my java application. I want to disappear the GUI and run the application in background, but system tray must remain available when user click on close button of JFrame.

Answer

I want to disappear the GUI and run the application in background, but
system tray must remain available when user click on close button of
JFrame.

• set proper JFrames method for DefaultCloseOperation, JFrame.setDefaultCloseOperation(HIDE_ON_CLOSE), by default implemented in API

Sets the operation that will happen by default when the user initiates a “close” on this frame. You must specify one of the following choices:

DO_NOTHING_ON_CLOSE (defined in WindowConstants): Don’t do anything; require the program to handle the operation in the
windowClosing method of a registered WindowListener object.

HIDE_ON_CLOSE (defined in WindowConstants): Automatically hide the frame after invoking any registered WindowListener objects.

DISPOSE_ON_CLOSE (defined in WindowConstants): Automatically hide and dispose the frame after invoking any registered WindowListener
objects.

EXIT_ON_CLOSE (defined in JFrame): Exit the application using the System exit method. Use this only in applications.

The value is set to HIDE_ON_CLOSE by default. Changes to the value of
this property cause the firing of a property change event, with
property name “defaultCloseOperation”.

• then from SystemTray to call JFrame.setVisible(true), this event is accesible from

  1. TrayIcon

  2. JPopupMenu added to SystemTray