[25816] in Athena Bugs
linux 9.3.8: /usr/java/j2re1.4.2_04/bin/java
daemon@ATHENA.MIT.EDU (Jacob Morzinski)
Fri Jul 16 18:03:52 2004
Message-Id: <200407162203.i6GM3mVC002178@alice-whacker.mit.edu>
To: bugs@mit.edu
Date: Fri, 16 Jul 2004 18:03:48 -0400
From: "Jacob Morzinski" <jmorzins@mit.edu>
Errors-To: bugs-bounces@mit.edu
System name: alice-whacker.mit.edu
Type and version: i686 9.3.8 (with mkserv)
Display type: ATI Technologies Inc 3D Rage Pro AGP 1X/2X (rev 5c)
Shell: /bin/sh
Window manager: unknown
What were you trying to do?
I was hoping to run the local disk "java" interpreter
on Linux, like I can on Solaris.
What's wrong:
A j2re is installed, but java isn't in the PATH.
What should have happened:
It would have been nice for "java" to run the JRE that is
installed in /usr/java/j2re1.4.2_04/bin/java
Please describe any relevant documentation references:
The RPM that installs the j2re doesn't create a link
in /usr/bin . I found mailing list archives that suggest
that the reason that people don't create a /usr/bin/java is
that they're afraid of the sitution where multiple JRE's
might be installed. (I.e., "Which jre should the
/usr/bin/java link point to?")
This doesn't seem to be a big problem for Athena ... people
who want to use multiple JRE's will probably pull them out
of AFS, where we already have a system for managing
versions. The presense of a local java interpreter on
Solaris doesn't seem to have interfered with this system.
If Athena decides that it would be a good idea to let the
Linux machines resemble the Solaris machines in having a
"java" binary, one way to add "java" to the path is to use
Linux's /etc/profile.d/*.{csh,sh} system to configure java.
For example, the following two java.sh and java.csh files
would extend a user's PATH so that "java" is available.
cat > /etc/profile.d/java.sh << 'EOF'
JAVA_HOME=/usr/java/j2re1.4.2_04
PATH="$PATH":"$JAVA_HOME"/bin
export JAVA_HOME PATH
EOF
cat > /etc/profile.d/java.csh << 'EOF'
setenv JAVA_HOME /usr/java/j2re1.4.2_04
set path = ( $path:q $JAVA_HOME:q/bin )
EOF
If a future RPM puts java in the PATH, backing out this
change will be as simple as removing these two files.
If RedHat upgrades the installed j2re, the script could be
made more intelligent about how it locates JAVA_HOME. See
the "for i in $jre_list" loop in the "GetLatestJavaWSPath()"
shell function in "rpm -q --scripts j2re-1.4.2_04-fcs".
Because these java.{csh,sh} files extend the PATH, repeated
execution of the files will repeatedly extend the path.
If this is a problem, the files could use /bin/athena/attach
instead of extending the PATH directly:
eval "`/bin/athena/attach -Padd $JAVA_HOME/bin`"
(Bash needs "attach -Padd -b")
Credit for /etc/profile.d/java.{csh,sh}:
http://www.redhat.com/archives/fedora-list/2003-December/msg01672.html
-Jacob
