Running Eclipse on JamVM and Classpath on OpenBSD

Since this was written lang/jamvm and lang/classpath have become prebuilt packages in OpenBSD -current, and jikes has been upgraded to 1.22p0.

Summary

• Install the prebuilt packages for fastjar-0.93, and zip-2.3p0 from your favorite mirror. This will avoid an unnecessary build of these packages using the ports tree.
• Replace lang/jikes with the port for jikes-1.22p0 and install it; jikes-1.22p0 recognizes the -encoding switch which is required for the build of classpath-0.20 (there are other needs as well.)
• Insert lang/jamvm and lang/classpath in the ports tree. Do a make install for jamvm, which depends on classpath.
• Insert the devel/exodus meta port in the ports tree and install it.
• Set your environment variables JAVA_HOME=/usr/local/exodus and PATH as is customary when using a JDK. This is a sufficient command line environment to run the java, javac and jikes commands. Later this article explains how to build the Java ports in OpenBSD.
• Setup Eclipse -- even if you don't have Sun's JDK installed (see below)
• Increase your max open files ulimit: ulimit -n 200
• Run eclipse

The script exodus.setup will do these steps. You will of course want to read the code before you decide to run it -- there is no warranty.

The full version follows.

Note: throughout this article relative paths are with respect to the root of OpenBSD ports tree: /usr/ports.

Installing JamVM + GNU Classpath

There are two ports needed for a free Java stack based on JamVM and GNU Classpath on OpenBSD -current (3.9-beta) [and which may work on 3.8 as well]:

• lang/jamvm based on JamVM 1.4.2
• lang/classpath based on GNU Classpath 0.20

Put these in your ports tree and build jamvm:

  cd /usr/ports/lang/jamvm
  sudo make install

There is an explicit dependency in jamvm on classpath so it will be automatically installed.

There are two implementations for JamVM and GNU Classpath on this site; they are matched sets:

JamVM	Classpath
1.4.1	0.19
1.4.2	0.20

The Exodus Meta Port

I created exodus.tar.gz as a meta port to make it easier to build and use existing Java ports on OpenBSD. It is an experiment to maintain updward compatible with the existing build structure and to leverage the existing ports on alternative JVMs. The Exodus package does three things:

1. creates a directory structure /usr/local/exodus with naming conventions as expected by Sun's JDK;
2. links to various files already installed; and
3. provide two files: devel/exodus/java.port.mk and a revised version of infrastructure/mk/java.port.mk (more about this below.)

To use it put the port in /usr/ports/devel/exodus and then install the Exodus package using:

  cd /usr/ports/devel/exodus
  sudo make install

The install will create the JAVA_HOME directory structure in /usr/local/exodus and populate it; it will also install a revised version of infrastructure/mk/java.port.mk; If you delete the package it will remove JAVA_HOME directory and restore java.port.mk to the original.

Using OpenBSD's Eclipse Port without Sun's JDK

  export JAVA_HOME=/usr/local/exodus
  export ECLIPSE_HOME=/usr/local/eclipse 
  export PATH="$JAVA_HOME/bin:$PATH"

#set the environment
  export LD_LIBRARY_PATH=$HOME/e/lib #do this if you faked out pkg_add
  export JAVA_HOME=/usr/local/exodus
  export ECLIPSE_HOME=$HOME/e/eclipse
  export PATH="$JAVA_HOME/bin:$PATH"
#classpath likes file descriptors:
  ulimit -n 200
  ulimit -d 500000
#run it
  eclipse

  cd devel/apache-ant
  sudo make MODJAVA_PROVIDER=exodus install

  ulimit -n 128
  ulimit -d 300000

You will need the port jikes-1.22p0 for Tomcat and Eclipse builds. It implements the -encoding switch by bringing in libiconv. (Earlier OpenBSD jikes port didn't provide libiconv, so -encoding was disabled.) To get Tomcat to use Jikes for JSP compiles you will need to modify /etc/tomcat/web.xml per the comments on setting the for compiler in the tag. You should also modify the /etc/tomcat/tomcat.rc file to include the following:

ulimit -n 128
CATALINA_OPTS=-Dbuild.compiler.emacs=true
JAVA_OPTS="-Xms30m -Xmx120m -Djava.net.preferIPV4Stack=true"

Compiling Eclipse 3.1 under Exodus

This is work in progress. As you can see from the above description, it's not really necessasry to compile Eclipse under Exodus. It's just a kind of super Mauve test. An Eclipse build is a three stage process; stage 1 bootstraps ecj using javac or jikes; stage 2 compiles ecj with itself; stage 3 builds the plugins using ecj. Stage three also builds platform dependent binaries using gcc and friends. The entire process requires Ant to work and patches to the build script that are not ready for public consumption.

At the moment I'm fussing with a linker error in stage 3 after 45 minutes of ecj Java compile. Stay tuned.

Conclusion

The Exodus meta package creates the kind of shim that many Java packages expect. This makes it easier to use the existing Java ports in OpenBSD. A related question is how to package the existing Java ports to permit the use of alternative JVMs. Perhaps some kind of convention for dependent libraries could be defined. Then any package that provides those libs would be judged as fulfilling the requirements for a JVM package. Although flavors might be useful we can see that the Eclipse port really does not need a different flavor to be run under JamVM and Classpath on OpenBSD.

Frederick C. Druseikis
fdruseikis at sc dot edu
http://www.cse.sc.edu/~fredd/
March 6, 2006