Re: Some observations on developing with gcj

[Tom Tromey <tromey at redhat dot com>]

>>>>> "Mark" == Mark Wielaard <mark@klomp.org> writes:

Mark> When closing the program down I wanted to use shutdown
Mark> hooks. But they only really work when the program terminates
Mark> cleanly. It would be nice if shutdown hooks were also triggered
Mark> when the program receives a fatal signal (such as the user
Mark> pressing Control-C).

Does the JDK do that?  This is worthy of a bug report.

Mark> java-gnome <http://java-gnome.sourceforge.net/> was surprisingly
Mark> usable. The main drawback is that it currently is only available
Mark> as jar files with jni libraries in Debian which means that you
Mark> will have to use gij at the moment.

It should be possible to just run "gcj -fjni" on the .jar file.  Well,
with gcj 3.3 this may not work perfectly, since the patch to compile
property files isn't in that release.  It might only take you a few
minutes to try it out...

Mark> When debugging your native program it is really unhelpful that
Mark> NullPointerExceptions don't point at where the actual exception
Mark> occured but at the calling method.

Please file in bugzilla.

Mark> When using the interpreter Kaffe is nicer since it gives line
Mark> numbers.

Try compiling with -g.  Or do you mean that gij doesn't give line
numbers?  That should go in bugzilla -- right now I think we drop this
information, but we could easily keep it around.

Mark> And using gdb with gij gives not that nice backtraces since you
Mark> can only see the interpreter frames.

Yeah.  Coincidentally I talked to Andrew Cagney about this problem
last week.  As it turns out, gdb has a lot of the infrastructure to
make it possible.  We just need somebody to actually work on it.  I
doubt it is very easy; it probably requires a gdb expert, plus some
additions to libgcj to make it possible for gdb to extract all the
information it needs.

Mark> [ binary compatibility ]
Mark> The two main problems that users have are PAM and iconv
Mark> (libraryy) loading which crashes the binary.

I think these are glibc problems.  At least I don't see what we could
do about it.

Longer term we want to push out the "new ABI" work, which will largely
insulate gcj users from library changes.

Mark> One thing that I didn't really tackle yet is creating a clean GNU
Mark> configure/make install with all the nice standard make targets. I
Mark> found automake a bit confusing and it didn't seem to handle the simple
Mark> application case and seems to insist on creating.

Send me private email with what you tried, and I'll take a look at it.
Maybe one or more automake bug reports are needed.  The java support
in automake is still pretty new.

Mark> Something that I learned from working on this project is that it is
Mark> really nice to have a irc channel to directly discuss some issues with
Mark> interested people. We should really consider setting up a gnu-java
Mark> channel on freenode. Are people interested in this?

Sure.  Like Jeff, lately I've been on #gcc on OFTC.  Anthony once
tried to start a #gcj, but I don't think many people showed up.
Anyway, tell me the channel and I'll be there.  We could also mention
it on our web page.

Tom