On some machines SystemTray.add throws exception although Java reports that SystemTray is supported

The issue can be observed with Java 7u1 on emb-spb-atom-d2700-1.ru.oracle.com

The attached program verifies that SystemTray is supported, then creates a TrayIcon, then adds the icon to the system tray.

However, when adding it throws AWTException which is unexpected since SystemTray is supported.

To reproduce login to emb-spb-atom-d2700-1.ru.oracle.com, put the attached program and the attached gif into the same folder and compile and run the program.

Below is the log from the attached program:

$ ejdk1.7.0/bin/java SysTrayTest
tray supported=true
tray=java.awt.SystemTray@188c5c2
image=sun.awt.image.ToolkitImage@36f58e
icon=java.awt.TrayIcon@c5e234
failed
java.awt.AWTException: TrayIcon couldn't be displayed.
at sun.awt.X11.XTrayIconPeer.<init>(XTrayIconPeer.java:254)
at sun.awt.X11.XToolkit.createTrayIcon(XToolkit.java:1144)
at java.awt.TrayIcon.addNotify(TrayIcon.java:689)
at java.awt.SystemTray.add(SystemTray.java:263)
at SysTrayTest.main(SysTrayTest.java:37)
Done