RH Enterprise Linux AS release 3
Kernel 2.4.21-15.0.2.ELsmp i686

We have students who use this server for Java programming classes.
They connect to the server via telnet.
They write their programs using text editors, compile using 'javac' and execute their programs using 'java'.
One problem that is being encountered is if they execute a program that is supposed to display labels, buttons, textfields or anything GUI related, the program will throw the following exception;

"Exception in thread "main" java.lang.InternalError: Can't connect to X11 window using ':0.0' as the value of the DISPLAY variable."


If the same program was executed in a terminal window at the console it would work as programmed.

My question is- how can the students get their GUI java apps to execute and display properly when connected to the server remotely?

Thanks!
-Giles

it can't be done the way you want it to be. when you connect via telnet all you get is the telnet terminal. with ssh you can use X11 forwording to make any gui apps display on the connecting machine, however that requires and X server (gui environment) to be running on the connecting machine. if you students use linux there is no problem they simply ssh serverIP
export DISPLAY="theirIP:0.0"
run the application.

if they use windows they have but one option. install cygwin and launch it's X server and ssh client.

I personaly have done all of this on my home systems.

I am a programming student, I took 3 java classes, we learned on windows at school, however I used linux, because fo java's cross platform ability I could develop on linux and it would run fine onthe instructors windows machine, and vice versa is true. you should have your students install the java VM on there windows boxes and upload there finished progrm to the server for grading.

as I stated before there is no easy way to do what you want. installing cygwin can be more difficult then installing linux. and I doubt most of your students use linux.

Thanks exodist.
Yes, the students are using WXP. I will look into cygwin.

Thanks again!