Re: libgcj/6819: duplicate class registration bug

Re: libgcj/6819: duplicate class registration bug

[Bryce McKinlay]

The following reply was made to PR libgcj/6819; it has been noted by GNATS.

From: Bryce McKinlay <bryce@waitaki.otago.ac.nz>
To: gcc-gnats@gcc.gnu.org
Cc:  
Subject: Re: libgcj/6819: duplicate class registration bug
Date: Mon, 27 May 2002 16:03:41 +1200

 http://gcc.gnu.org/cgi-bin/gnatsweb.pl?cmd=view%20audit-trail&database=gcc&pr=6819
 
 Yes, this is a well known issue. The problem is that if we have 
 duplicated symbols (ie the same symbol representing both old and new 
 versions of a class), it is quite non-deterministic (or at least 
 non-portable) which of them will actually be found and used at runtime 
 by the linker.
 
 This should be fixable in conjunction with implementing a weaker linking 
 model - this is also needed for strict adherance to Java's binary 
 compatibility spec, and would allow us to do cool things like link 
 compiled classes against interpreted class files, etc.
 
 Bryce.
 
 

libgcj/6819: duplicate class registration bug

[Oskar Liljeblad]

>Number:         6819
>Category:       libgcj
>Synopsis:       duplicate class registration bug
>Confidential:   no
>Severity:       serious
>Priority:       medium
>Responsible:    unassigned
>State:          open
>Class:          sw-bug
>Submitter-Id:   net
>Arrival-Date:   Sun May 26 08:36:00 PDT 2002
>Closed-Date:
>Last-Modified:
>Originator:     Oskar Liljeblad <oskar@osk.mine.nu>
>Release:        3.1
>Organization:
>Environment:

>Description:
This is probably an old and known problem:

If you compile a class that also exists in libgcj into an executable, you'll get an error like this when running the executable:

libgcj failure: Duplicate class registration: org.w3c.dom.Attr
Aborted

Note that the same problem does not occur when running the class with gij.

This (probably) means that if you compile your program with a version of libgcj which doesn't contain class Y, it is not possible to run this program with a newer version of libgcj which does contain class Y. (Granted class Y is compiled into the program in the first place.)
>How-To-Repeat:

>Fix:

>Release-Note:
>Audit-Trail:
>Unformatted: