Re: [Jython-users] Problem with imports

[Sébastien B. <seb...@te...>]

    Hi all,

Replying to my own question, it seems that I was kinda tired yesterday afternoon, because this morning I could easily find some  ressources explaining the phenomenon, indeed.

So far, I've found a thread from 2008
  http://python.6.x6.nabble.com/Problem-importing-Java-packages-td1773276.html
and as long as I import classes instead of packages, everythong is fine (using the standalone mode).

I have also found some information in the Jython Book[1] which led me to use 'jython' (not the standalone version), with the '-Djava.ext.dirs="/dir/with/my/jar(s)/inside/"

I guess this is sufficient for me starting to use jython.
I have also seen that it is possible to repack the .jar to provide the necessary classes inside a single jar, for distribution [2], so I keep that under the pillow.

In any case, if I forgot an obvious solution with the standalone jython in particular, I'd be glad to here from it; especially because it is simpler to use.  And I say something wrong, I'd be grateful that someone points them --I'm just starting to use jython.

Best regards,
__ Sébastien.

[1] http://www.jython.org/jythonbook/en/1.0/ModulesPackages.html#how-jython-finds-the-jars-and-classes-to-scan
[2] https://wiki.python.org/jython/LearningJython#id62


On Fri, 13 May 2016 17:59:23 +0200 Sébastien Bigaret <seb...@te...> wrote:
>     Hi all,
> 
> I have currently a problem with imports I do not understand.
> This is what happens (Jython 2.7.0, java 1.8.0u66, on debian 8):
> 
> ----8< ---- 8< ----
> ./jython.sh
> Jython 2.7.0 (default:9987c746f838, Apr 29 2015, 02:25:11) 
> [Java HotSpot(TM) 64-Bit Server VM (Oracle Corporation)] on java1.8.0_66
> Type "help", "copyright", "credits" or "license" for more information.
> >>> import sys; sys.path  
> ['', '/path/to/XMCDA-java.jar', '/home/bigaret/lang/python/Lib', '/home/bigaret/lang/python/jython-standalone-2.7.0.jar/Lib', '__classpath__', '__pyclasspath__/']
> >>> import org.xmcda.parsers.xml   # this one fails here....  
> Traceback (most recent call last):
>   File "<stdin>", line 1, in <module>
> ImportError: No module named xmcda
> >>> from org.xmcda.parsers.xml.xmcda_3_0 import XMCDAParser
> >>> import org.xmcda.parsers.xml   # ...but now it succeeds
> >>> org.xmcda.parsers.xml  
> <java package org.xmcda.parsers.xml 0x2>
> >>> sys.path  
> ['', '/path/to/XMCDA-java.jar', '/home/bigaret/lang/python/Lib', '/home/bigaret/lang/python/jython-standalone-2.7.0.jar/Lib', '__classpath__', '__pyclasspath__/']
> ----8< ---- 8< ----
> 
> 
> Note that the first import fails, while the last (which is the same statement) succeeds --and sys.path was untouched, there is just an import between the two identical imports)
> 
> Does someone has any hint why I get such a strange behaviour, or can point me to the right documentation to read? I could unfortunately not find any hint on such peculiarities when searching in jython's doc or on the web in general.
> 
> Thanks in advance,
> 
> __ Sébastien.
> 
> 
> NB: The jython.sh is a simple bash script:
> 
> ----8< ---- 8< ----
> #! /bin/bash
> JAVA=/usr/local/java8/bin/java
> JYTHON_STANDALONE_JAR=/home/bigaret/lang/python/jython-standalone-2.7.0.jar
> XMCDA_LIB="/path/to/XMCDA-java.jar"
> 
> export JYTHONPATH="${XMCDA_LIB}"
> 
> "${JAVA}" -cp "${JYTHON_STANDALONE_JAR}" org.python.util.jython
> ----8< ---- 8< ----
> 
> (and I have the same behaviour when adding XMCDA_LIB to the java '-cp' argument.
>