Programming

Hello,
I'm running tomcat on linux and using Xvfb as a X server for creating the pdf's (gui components).
I'm running the Xvfb in a different proccess than the tomcat.
If the Xvfb is shutdown and no pdf was yet created then everything is ok.
but if i create a pdf and then shutdown the Xvfb then the tomcat crashes,i think its because the open connection the between the Xvfb and the tomcat.
i only receive this message in the tomcat log:
"X connection to :50 host broken (explicit kill or server shutdown)"
I tried to close all the connection but it stills crashes.
I raise the Xvfb like so:
Xvfb -ac :50 -screen 0 1280x1024x8

Thanks,
Omer C