Jython Monthly July 2006 Articles

Standalone mode - Libraries included

Jython has now a standalone mode, where the core part is all included in one single jython.jar file. This has two advantages:

• simpler starting: java -jar jython.jar

• simpler embedding: just put jython.jar onto your classpath. No setting of python.home nor python.path required.

This really adds a Plug & Play feature to Jython.

There is a preview available ([http://homepage.sunrise.ch/mysunrise/ohumbel/jython_2837.jar snapshot build]).

A sample install and run session, after downloading jython_2837.jar:

[root@localhost downloads]# java -jar jython_2837.jar -s -d /tmp/jython_standalone -t standalone
Performing silent installation
 10 %
 20 %
 30 %
 40 %
 50 %
 60 %
 70 %
 80 %
Packing standalone jython.jar ...
 90 %
 100 %
Congratulations! You successfully installed Jython HEAD to directory /tmp/jython_standalone.

[root@localhost downloads]# cd /tmp/jython_standalone/
[root@localhost jython_standalone]# ls
jython.jar

[root@localhost jython_standalone]# java -jar jython.jar 
*sys-package-mgr*: processing new jar, '/tmp/jython_standalone/jython.jar'
*sys-package-mgr*: processing new jar, '/usr/java/jre1.5.0_07/lib/rt.jar'
*sys-package-mgr*: processing new jar, '/usr/java/jre1.5.0_07/lib/jsse.jar'
*sys-package-mgr*: processing new jar, '/usr/java/jre1.5.0_07/lib/jce.jar'
*sys-package-mgr*: processing new jar, '/usr/java/jre1.5.0_07/lib/charsets.jar'
*sys-package-mgr*: processing new jar, '/usr/java/jre1.5.0_07/lib/ext/sunjce_provider.jar'
*sys-package-mgr*: processing new jar, '/usr/java/jre1.5.0_07/lib/ext/localedata.jar'
*sys-package-mgr*: processing new jar, '/usr/java/jre1.5.0_07/lib/ext/sunpkcs11.jar'
*sys-package-mgr*: processing new jar, '/usr/java/jre1.5.0_07/lib/ext/dnsns.jar'
Jython 2.2a1 on java1.5.0_07 (JIT: null)
Type "copyright", "credits" or "license" for more information.
>>> import sys
>>> sys.path
['', '/tmp/jython_standalone/.', '/tmp/jython_standalone/./Lib', '/tmp/jython_standalone/jython.jar/Lib']
>>> import getopt
>>> 

One Open issue: the cachedir problem still remains. If the directory containing jython.jar is not writable, no cachedir will help importing java classes. This is a well known problem also persistent in non-standalone mode. We try to improve this in standalone mode.