Exception in thread "main" java.awt.HeadlessException

Issue

• How to confirm you are using headless mode?
• How to set up headless mode in Java explicitly?
• Customer getting below error while starting the GUI of Java application :

[user@user bin]# exampleGUIApplicaion
openjdk version "1.8.0_282"
OpenJDK Runtime Environment (build 1.8.0_282-b08)
OpenJDK 64-Bit Server VM (build 25.282-b08, mixed mode)
Exception in thread "main" java.awt.HeadlessException
        at java.awt.GraphicsEnvironment.checkHeadless(GraphicsEnvironment.java:204)
        at java.awt.Window.<init>(Window.java:536)
        at java.awt.Frame.<init>(Frame.java:420)
        at java.awt.Frame.<init>(Frame.java:385)
        at javax.swing.SwingUtilities$SharedOwnerFrame.<init>(SwingUtilities.java:1763)
        at javax.swing.SwingUtilities.getSharedOwnerFrame(SwingUtilities.java:1838)
        at javax.swing.JWindow.<init>(JWindow.java:187)
        at javax.swing.JWindow.<init>(JWindow.java:139)
        at xxx.client.C_MainFrame$18.<init>(C_MainFrame.java:1048)
        at xxx.client.C_MainFrame.showSplash(C_MainFrame.java:1048)
        at xxx.client.C_MainFrame.main(C_MainFrame.java:1008)