I have a pair of Java programs that use JTable to display lists of 
database content. These run under Redhat Linux Fedora 8 in the Java 6 SE 
edition 1.6.0_05. 

If I login from the host's console everything works as expected, but if I 
login via ssh with X11 forwarding from a laptop running Fedora 9 and run 
the applications, then scrolling the lists quickly turns them into rows 
of black, unreadable 'Chinese writing' as the glyphs in each row are 
overwritten without being cleared first.

The problem doesn't occur if I use an ssh login from an old laptop 
running Fedora 1.

Questions:
- has anybody else seen this problem?

- is it confined to Fedora 9 (and probably the version of X.11 -
  xorg-x11-server 1.4.99.905-2.20080702.fc9) or has it been seen
  under other OSes or Linux distros?

- is there a known fix?


-- 
martin@   | Martin Gregorie
gregorie. | Essex, UK
org       |

Martin Gregorie wrote:

> I have a pair of Java programs that use JTable to display lists of 
> database content. These run under Redhat Linux Fedora 8 in the Java 6 SE 
> edition 1.6.0_05. 
> 
> If I login from the host's console everything works as expected, but if I 
> login via ssh with X11 forwarding from a laptop running Fedora 9 and run 
> the applications, then scrolling the lists quickly turns them into rows 
> of black, unreadable 'Chinese writing' as the glyphs in each row are 
> overwritten without being cleared first.
> 
> The problem doesn't occur if I use an ssh login from an old laptop 
> running Fedora 1.
> 
> Questions:
> - has anybody else seen this problem?

I have never seen that problem on any Linux/Java combination I've used.

> 
> - is it confined to Fedora 9 (and probably the version of X.11 -
>   xorg-x11-server 1.4.99.905-2.20080702.fc9) or has it been seen
>   under other OSes or Linux distros?
> 
> - is there a known fix?
> 
> 

That certainly sounds like a local X server or display driver problem. It
probably isn't refreshing correctly. Do you have any options turned on with
regard to local caching in the X server, backing-store or save-unders?

Are you able to run the application locally on the Fedora 9 box? Does the same
problem manifest itself there?

I don't have any locally installed Fedora 9 boxes so can only test with a LiveCD
version. I don't see the problem you do. However, I probably have different
video hardware, drivers, X11 version, Java version etc. The video driver is the
generic "intel" one, X11 is 1.4.99.901, Java on the remote system is 1.6.0_07. 

-- 
Nigel Wade

In article <g90pb7$3dj$1@localhost.localdomain>,
 Martin Gregorie <martin@see.sig.for.address.invalid> wrote:

> I have a pair of Java programs that use JTable to display lists of 
> database content. These run under Redhat Linux Fedora 8 in the Java 6 SE 
> edition 1.6.0_05. 
> 
> If I login from the host's console everything works as expected, but if I 
> login via ssh with X11 forwarding from a laptop running Fedora 9 and run 
> the applications, then scrolling the lists quickly turns them into rows 
> of black, unreadable 'Chinese writing' as the glyphs in each row are 
> overwritten without being cleared first.
> 
> The problem doesn't occur if I use an ssh login from an old laptop 
> running Fedora 1.
> 
> Questions:
> - has anybody else seen this problem?
> 
> - is it confined to Fedora 9 (and probably the version of X.11 -
>   xorg-x11-server 1.4.99.905-2.20080702.fc9) or has it been seen
>   under other OSes or Linux distros?
> 
> - is there a known fix?

Does the X11 server that's running on Fedora 9 have a default language 
set? What about the X11 server running on the old Fedora 1? Does the 
same thing happen with VNC, under which the (virtual) X11 server runs on 
the host?

-- 
John B. Matthews
trashgod at gmail dot com
home dot woh dot rr dot com slash jbmatthews

On Tue, 26 Aug 2008 15:32:19 +0100, Nigel Wade wrote:

> Martin Gregorie wrote:
>> Questions:
>> - has anybody else seen this problem?
> 
> I have never seen that problem on any Linux/Java combination I've used.
>
Thanks for that - its useful information. 

> That certainly sounds like a local X server or display driver problem.
> It probably isn't refreshing correctly. Do you have any options turned
> on with regard to local caching in the X server, backing-store or
> save-unders?
> 
> Are you able to run the application locally on the Fedora 9 box? Does
> the same problem manifest itself there?
>
Sorry about the slow reply, but running on the Fedora 9 box has been on 
my 'todo' list, i.e. running the GUI programs as true client-server 
programs across my LAN with the database remaining on my house server. 
That's my main development box and is still running Fedora 8. I normally 
develop over an ssh connection which forwards X11 so I can run the 
graphical apps.

As a consequence to run the applications natively under Fedora 9 I had to 
solve one or two problems I'd been sidestepping:

- finally working out how to make Postgres accept connections other
  than just from localhost. Easy enough when I fiddled my way to finding
  the syntax it would accept, bit its pickier than the documentation
  indicates [didn't like a comment at the end of the 'listener' line]
  and the server error messages are almost nonexistent.

- bringing the F9 box's CLASSPATH and jarlib collection into line with
  those on the F8 box.

Anyway, thanks for making me tackle those details.

The end result is that the JTable 'chinese writing' ugliness vanished 
when I ran the app locally on the F9 box, so its something to do with ssh 
and X11 forwarding.

That's interesting: I often run OpenOffice this way and sometimes do it 
with Opera, but the only time I've seen this window corruption is with 
Java 6 and F9. Neither J2SE 1.4 or J6 showed this effect with my old 
laptop, which runs Fedora 1.

Anyway, thanks for asking the right questions to make me locate the 
problem.


-- 
martin@   | Martin Gregorie
gregorie. | Essex, UK
org       |