Default CLASSPATH for multi-user systems

[Chris De Vries]

I administer a linux box with many java users. I noticed that many users downloaded several jakarta projects or other open source projects and included the relevant jars in their own directories, and manually edited their CLASSPATH each time they added a jar. I decided to make a central repository (/usr/local/jars) for all the jars, and make a csh script to automatically set the classpath as well as some other variables. I figured I would share it in case anyone else wants to use it, translate it to bash, or offer suggestions.
I have put this in /etc/javasetup.csh:

# set JAVA_HOME to your sdk location
setenv JAVA_HOME /usr/local/j2sdk1.4.2
# set jar_home to the location of your jars
set jar_home = /usr/local/jars
# Set the CLASSPATH
if(! $?CLASSPATH) then
  setenv CLASSPATH .
endif
if(! $?nonomatch) then
  set nonomatch
  set reclassundononomatch
endif
set jj = ${jar_home}/*.jar
foreach jar ($jj)
  if (-e $jar) then
    setenv CLASSPATH ${CLASSPATH}:${jar}
  endif
end
if ($?reclassundononomatch) then
  unset nonomatch
  unset reclassundononomatch
endif
# add java to path
set path=(${JAVA_HOME}/bin $path)

And now all I have to do to add more jars is to either move it into /usr/local/jars or make a symbolic link from /usr/local/jars to the package. All users can include the line "source /etc/javasetup.csh" in their .cshrc file. It also allows me to update the jdk and merely change one line in the javasetup.csh to allow all users to use the updated jdk.
I have tried making a sh/bash script too, though my knowledge of bash is limited.

# set JAVA_HOME
JAVA_HOME=/usr/local/j2sdk1.4.2
export JAVA_HOME
# set jar home
jar_home=/usr/local/jars
# set CLASSPATH
if [ -z "$CLASSPATH" ]; then
  CLASSPATH=.
fi
for i in ${jar_home}/*.jar; do
  CLASSPATH=$CLASSPATH:$i
done
export CLASSPATH
# set PATH
PATH=$JAVA_HOME/bin:$PATH
export PATH

Please feel free to use/modify/point out any bugs or platforms where these don't work. Or offer suggestions on what you have done differently.
Chris

[Pankaj Kr]

Be ready to deal with a lot of broken Apps
I have spent countless hours of debugging due to the wrong xalan.jar or xerces.jar in my application. And this is when I could control my own jar files and CLASSPATH! Imagine what would happen if someone else was constantly modifying the CLASSPATH and the jar files!

[Chris De Vries]

No one has to use the CLASSPATH I define, and so far it's working well. If a particular package becomes a problem, then we can figure out if we want to exclude it from the scheme or not. Right now we don't have xalan.jar or xerces.jar in the /usr/local/jars directory.
Also, this is not a huge multiuser system... Only 12 users in one workgroup, so communication is not as big an issue as if it were a 100 user system.
That said, I am worried that someone might request that a jar be updated only to find that it breaks someone else's application. In that case, I'm not sure what we could do to consolidate. For that jar we would probably stick with the old version and the user who needs the new version would manually use the new version.
Right now only 5 of the users (including myself) are using the csh script, and no one is using the bash one.
Chris
[ October 08, 2003: Message edited by: Chris De Vries ]

[Adrian Yan]

my script:

 # contains machine specific environment variables
# should be source by /etc/profile
# set up java ralated environment
JAVA_HOME=/usr/local/share/j2sdk1.4.2_01
JAVA_LIB=/usr/local/share/java
# Extra libraries
DIRLIBS=$JAVA_LIB/*.jar
for i in ${DIRLIBS} 
    do
        CLASSPATH="$i":$CLASSPATH
done
export JAVA_HOME JAVA_LIB CLASSPATH