JRuby

Calling JRuby from MATLAB/Octave fails at enumerator library

Details

  • Type: Bug Bug
  • Status: Resolved Resolved
  • Priority: Minor Minor
  • Resolution: Incomplete
  • Affects Version/s: JRuby 1.4.0RC1
  • Fix Version/s: None
  • Component/s: Embedding
  • Labels:
    None
  • Environment:
    MATLAB R2009b with JVM 1.6 on WinXP;
    Octave 3.2.3 with JVM 1.5 on Leopard PPC
  • Testcase included:
    yes
  • Number of attachments :
    0

Description

MATLAB and Octave, two environments that can call into Java libraries, both encounter errors when they try to call into JRuby. Here's a MATLAB interaction demonstrating the behavior:

>> javaaddpath 'C:\jruby-complete.jar' 
>> import org.jruby.Main; 
>> jruby = Main(); 
>> jruby.run('--version'); 
jruby 1.5.0dev (ruby 1.8.7 patchlevel 174) (2009-10-16 6586) (Java HotSpot(TM) Client VM 1.6.0_16) [x86-java] 
??? Java exception

To log the contents of that exception, I stuck a custom Java class in between MATLAB and JRuby, and caught a NullPointerException with the message: library `enumerator' could not be loaded.

At first, I suspected a bug in MATLAB, since the equivalent Java code is able to call into JRuby. But then, see this interaction with Octave on a completely different platform:

octave-3.2.3:1> pkg load java;
octave-3.2.3:2> java_init;
octave-3.2.3:3> javaaddpath("/Users/username/jruby-complete.jar")
octave-3.2.3:4> java_invoke("org.jruby.Main", "main", {"--version"});
jruby 1.5.0dev (ruby 1.8.7 patchlevel 174) (2009-10-17 6586) (Java HotSpot(TM) Client VM 1.5.0_20) [ppc-java]
error: [java] org.jruby.exceptions.RaiseException: library `enumerator' could not be loaded: java.lang.ClassNotFoundException: org.jruby.libraries.EnumeratorLibrary

Are MATLAB and Octave doing something funky with class loaders? This issue is an obstacle to extending these environments in JRuby, since the exception occurs before any extension (using the Ruby-embed APIs) can run.

Activity

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Charles Oliver Nutter added a comment -

At least take a look for 1.4, and otherwise bump to 1.5.

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Charles Oliver Nutter added a comment - At least take a look for 1.4, and otherwise bump to 1.5.
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Ian Dees added a comment -

The MathWorks people have a workaround for the MATLAB case: if you add jruby-complete.jar to MATLAB's load-time classpath (by adding its path to a file called classpath.txt), then calling into JRuby works fine, both simple and JRuby-Embed cases.

Looking at the Octave source code, it seems like it would be easy enough to patch it to add a similar feature. I'll investigate.

(It still may be worth changing JRuby's doing initialization-time behavior here, but the presence of workarounds significantly diminishes the impact of this issue.)

Show
Ian Dees added a comment - The MathWorks people have a workaround for the MATLAB case: if you add jruby-complete.jar to MATLAB's load-time classpath (by adding its path to a file called classpath.txt ), then calling into JRuby works fine, both simple and JRuby-Embed cases. Looking at the Octave source code, it seems like it would be easy enough to patch it to add a similar feature. I'll investigate. (It still may be worth changing JRuby's doing initialization-time behavior here, but the presence of workarounds significantly diminishes the impact of this issue.)
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Thomas E Enebo added a comment -

A fix was put on master (9407eea). Ian, can you try it and make sure things work now? If it does we will back-port this to 1.4 branch.

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Thomas E Enebo added a comment - A fix was put on master (9407eea). Ian, can you try it and make sure things work now? If it does we will back-port this to 1.4 branch.
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Ian Dees added a comment -

Definite progress. I can do the equivalent of jruby --version and jruby -e "puts 42" from Octave.

The following JRuby-Embed code gives me an error, though:

octave-3.2.3:1> pkg load java;
octave-3.2.3:2> java_init;
octave-3.2.3:3> javaaddpath("/Users/username/jruby-complete.jar");
octave-3.2.3:4> container = java_new("org.jruby.embed.ScriptingContainer");
octave-3.2.3:5> java_invoke(container, "runScriptlet", "puts 42");
error: [java] org.jruby.exceptions.RaiseException: cannot load Java class org.jruby.ast.Node

This PPC machine is getting in the way of trying a different approach (such as JSR-223); I'll try Java 6 on a Macintel, and then move on to MATLAB on XP.

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Ian Dees added a comment - Definite progress. I can do the equivalent of jruby --version and jruby -e "puts 42" from Octave. The following JRuby-Embed code gives me an error, though: octave-3.2.3:1> pkg load java; octave-3.2.3:2> java_init; octave-3.2.3:3> javaaddpath("/Users/username/jruby-complete.jar"); octave-3.2.3:4> container = java_new("org.jruby.embed.ScriptingContainer"); octave-3.2.3:5> java_invoke(container, "runScriptlet", "puts 42"); error: [java] org.jruby.exceptions.RaiseException: cannot load Java class org.jruby.ast.Node This PPC machine is getting in the way of trying a different approach (such as JSR-223); I'll try Java 6 on a Macintel, and then move on to MATLAB on XP.
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Ian Dees added a comment -

Okay, big build problems standing in the way of Octave on Snow Leopard for now. On to MATLAB. JRuby main works now. JRuby-Embed throws an exception.

On Tom's suggestion, I tried invoking org.jruby.ast.Node(INVALID_POSITION) and got java.lang.InstantiationException: org.jruby.ast.Node

Show
Ian Dees added a comment - Okay, big build problems standing in the way of Octave on Snow Leopard for now. On to MATLAB. JRuby main works now. JRuby-Embed throws an exception. On Tom's suggestion, I tried invoking org.jruby.ast.Node(INVALID_POSITION) and got java.lang.InstantiationException: org.jruby.ast.Node
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Charles Oliver Nutter added a comment -

Ian; can you paste the whole InstantiationException please?

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Charles Oliver Nutter added a comment - Ian; can you paste the whole InstantiationException please?
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Thomas E Enebo added a comment -

Ran out of time for full resolution of this. Pending more information or things to try detargetting to 1.1+.

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Thomas E Enebo added a comment - Ran out of time for full resolution of this. Pending more information or things to try detargetting to 1.1+.
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Ian Dees added a comment -

Hi, Charlie.

All MATLAB reports is:

?? Java exception occurred:
java.lang.InstantiationException: org.jruby.ast.Node
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Ian Dees added a comment - Hi, Charlie. All MATLAB reports is: ?? Java exception occurred: java.lang.InstantiationException: org.jruby.ast.Node
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Charles Oliver Nutter added a comment -

Huh, that's pretty baffling. I have no other ideas to try. Maybe we could find someone at MATLAB that might be able to help us debug what's happening?

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Charles Oliver Nutter added a comment - Huh, that's pretty baffling. I have no other ideas to try. Maybe we could find someone at MATLAB that might be able to help us debug what's happening?
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Charles Oliver Nutter added a comment -

Old issue, specific to a single application's Java embedding capability. If there's something we can fix, reopen.

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Charles Oliver Nutter added a comment - Old issue, specific to a single application's Java embedding capability. If there's something we can fix, reopen.

People

  • Assignee:
    Charles Oliver Nutter
    Reporter:
    Ian Dees
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Dates

  • Created:
    Updated:
    Resolved: