[jruby-user] Using java -jar jruby.jar does not pick up environment CLASSPATH

[Johnny P]

Using a bash shell script such as:

CLASSPATH=foo.jar:build/:lib/
export CLASSPATH
java -jar jruby.jar myruby.rb

Inside myruby.rb

puts ENV['CLASSPATH']
require 'java'
#....


The classpath prints correctly; However, when I import, or use anything from that classpath I get class not found exceptions.  I cannot seem to find anyway to fix this.  TIA for any help.

PS:  Using jruby myruby.rb works fine, but I want to launch using java -jar jruby.jar.

TIA

[Damian Steer]

On 21 Jun 2008, at 00:46, Johnny P wrote:

> Using a bash shell script such as:
>
> CLASSPATH=foo.jar:build/:lib/
> export CLASSPATH
> java -jar jruby.jar myruby.rb

A classic java gotcha!

From the java man page section on -jar:

"When you use this option, the JAR file is the source of all user
classes, and other user class path settings are ignored."

So either 1) don't use -jar or 2) require 'my.jar'.

Damian

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[dennis zhuang]

put this statement in your ruby script

CLASSPATH="foo.jar:build/:lib/"

2008/6/21 Damian Steer <pl...@mac.com>:

[Johnny P]

Thanks Damian.  I ended up just putting the jruby jar in the -classpath on the command line then I used org.jruby.Main as the main class.  That worked.

Dennis setting/changing the CLASSPATH const does not work.  For example

# myruby.rb
CLASSPATH="spring.jar"
import org.springframework.context.support.ClassPathXmlApplicationContext;

$ jruby myruby.rb

You will get class not found ClassPathXmlApplicationContext.  Where if you do:
$ export CLASSPATH="spring.jar"
# myruby2.rb
import org.springframework.context.support.ClassPathXmlApplicationContext;

$ java org.jruby.Main -w myruby2.rb

That will work.  Yes you can require "spring.jar", but that does not help when you need to reference ".class, .xml, .properties" files expected in the classpath.  Thanks

[Vladimir Sizikov]

Hi Johnny,

On Tue, Jun 24, 2008 at 1:09 AM, Johnny P <jpyw...@gmail.com> wrote:
> Thanks Damian. I ended up just putting the jruby jar in the -classpath on
> the command line then I used org.jruby.Main as the main class. That worked.
>
> Dennis setting/changing the CLASSPATH const does not work. For example
>
> # myruby.rb
> CLASSPATH="spring.jar"
> import org.springframework.context.support.ClassPathXmlApplicationContext;

The code should be a bit different, you should use $CLASSPATH global variable,
it is an array, and you need to add your JAR files there:

$CLASSPATH << "ant.jar"
import org.apache.tools.ant.AntClassLoader

This works wine for me.

Thanks,
--Vladimir

[Johnny P]

Vladimir, thanks, but it does not work for all class path cases.  For example Spring.  If you use the spring class path xml app context the below fails.  I believe the reason why is because this circumvents the jruby url class loader.  So, being able to set the CLASSPATH outside the script could be essential.  I would imagine in Springs case I could use ruby to load the context and then pass the file contents to it, but I did not investigate that.

Thanks

[Stephen Bannasch]

At 3:44 PM -0700 6/24/08, Johnny P wrote:
>Vladimir, thanks, but it does not work for all class path cases. For example Spring. If you use the spring class path xml app context the below fails. I believe the reason why is because this circumvents the jruby url class loader. So, being able to set the CLASSPATH outside the script could be essential. I would imagine in Springs case I could use ruby to load the context and then pass the file contents to it, but I did not investigate that.
>
>Thanks

Hi Johnny,

I think this Jira bug report I entered about 6 weeks ago might describe the underlying cause for the problem you are having.

http://jira.codehaus.org/browse/JRUBY-2495
Requiring and using a Java library that ends up using a Thread Context classloader doesn't work.

I included a simplified test case but have had no comments yet from anybody.

[Vladimir Sizikov]

Hi Stephen, Johnny,

On Wed, Jun 25, 2008 at 3:20 AM, Stephen Bannasch

> I think this Jira bug report I entered about 6 weeks ago might describe the underlying cause for the problem you are having.
>
> http://jira.codehaus.org/browse/JRUBY-2495
> Requiring and using a Java library that ends up using a Thread Context classloader doesn't work.

Yes, that's the same issue. Also, I've encountered another case when
proper thread context classloader is required: loading JDBC drivers
that are not on CLASSPATH.

Luckily, there is a more or less straightforward way to adjust the
context classloader:
require 'jruby'
java.lang.Thread.currentThread.setContextClassLoader(JRuby.runtime.jruby_class_loader)

With that, I verified that the test case from the bug report pass. And
JDBC drivers are loaded OK too.

[Johnny P]

Vladimir and Stephen thanks.  java.lang.Class.forName was still not happy and I was getting ClassNotFound; However, thankfully for_name is overloaded and I swithed the call to for_name("my.java.class", false, JRuby

.runtime.jruby_class_loader)

To summarize I used the following:
require 'java'
require 'jruby'

["#{File.dirname __FILE__}/../build/", "#{File.dirname __FILE__}/../lib/"].concat(Dir["#{File.dirname __FILE__}/../lib/*.jar"]).each { |jar| $CLASSPATH << jar }
java.lang.Thread.currentThread.context_class_loader = JRuby.runtime.jruby_class_loader
#... and
jklass = java.lang.Class.for_name("com.company.JavaClass", false, JRuby.runtime.jruby_class_loader)

That did the trick.  Thanks to all.