Graphic display in Linux

In Oracle Linux Virtual Box VM, by default the graphic output is disabled. Login as root (su) and edit the file /etc/inittab as shown below

Subsequently from the command prompt run startx to start the graphic display.

It's possible that despite the above changes, errors like below may occur

[bea@vin2 Desktop]$ java -jar wls1036_generic.jar 
Xlib: connection to ":0.0" refused by server
Xlib: Invalid MIT-MAGIC-COOKIE-1 key
Unable to instantiate GUI, defaulting to console mode.

Solution:

Login as root and copy and override the .Xauthority from root's home folder to the user's home folder. As a precaution, take a backup of the user's .Xauthority file.

You can check if the graphic display is working or not by running xclock