AWT, linux and xserver

Question

hello
i have a servlet which manipulate gif images
it works on my local machine (WinXP)
but when i try to run it on a linux server mandrake (with apache)
it fails.
knowing that in the first execution i have the following error
"Can`t connect to X11 window server using `:0.0` as the value of the DISPLAY variable."
And after i always still have the following error:
"java.lang.NoClassDefFoundError: sun/awt/motif/MToolkit
at org.apache.jserv.JServConnection.processRequest(JServConnection.java:
320)
at org.apache.jserv.JServConnection.run(JServConnection.java:188)
at java.lang.Thread.run(Thread.java:475)"
i think that this problem occurs in my servlet when executing this instruction:
Image awtImage = Toolkit.getDefaultToolkit().getImage (...)
the Xserver is already activated on my linux server
the enviroment variable DISPLAY has the value:
DISPLAY=localhost:0.0
(notice i try DISPLAY=:0.0 and DISPLAY=131.107.0.40:0.0 and DISPLAY=:0
but i have also exactly the same errors)
i had execute "xhost +localhost" to allow my machine(which is the linux server)
to access the Xserver
knowing that i run my servlet on the same machine
do you have any idea?
thanks
hajar

Answer 1

Does your linux server have a monitor attached to it? I have run into numerous problems with Solaris machines running "off the shelf" graphics software (JClass ServerChart, NetBeans NetCharts, etc) where headless machines (i.e. no monitor) will not render the graphics. What you need is the xvfb application (X Virtual Frame Buffer). (A nice beefy 80MB download....) I apologize, I don't have the URL on where you can get it, try google. Essentially what happens is there is no where for the machine to push windows for rendering, even if you have an XServer running. xvfb acts as a virtual monitor (frame buffer). What you are experiencing sounds very similar. If you do have a monitor attached to it, completely disregard this and disavow all knowledge of my existence.... :-)