Fails to run the script as Jython. But works with python without any issue

Question

I'm kinda newbie to Jython. I'm trying to execute a python script through a Java program (using Jython). Inside the python script I'm trying to call a method of some external library (called petl). When I try to execute the script with python (As: python script.py) it executes without any problem. But when I try to access the script with Jython (As: jython script.py) it gives me the following error.

P.S: I can run simple python scripts without any problem. But when I try to access an external library function through the script it gives me an error.

Can anyone please give me an workaround or some advice? Thanks in advance.

Python Script:

import petl as etl
table1 = etl.fromcsv('Books.csv')
table2 = etl.sort(table1, 'ACCOUNT_ID')
etl.tocsv(table2, source='NewBooks.csv',encoding='utf-8')

Error Stack:

Traceback (most recent call last):
 File "test1.py", line 5, in <module>
 etl.tocsv(table2, source='NewBooks.csv',encoding='utf-8')
 File "C:\Jython\Lib\site-packages\petl\io\csv.py", line 106, in tocsv
 tocsv_impl(table, source=source, encoding=encoding, errors=errors,
 File "C:\Jython\Lib\site-packages\petl\io\csv_py2.py", line 50, in tocsv_impl
 _writecsv(table, source=source, mode='wb', **kwargs)
 File "C:\Jython\Lib\site-packages\petl\io\csv_py2.py", line 74, in _writecsv
 for row in rows:
 File "C:\Jython\Lib\site-packages\petl\transform\sorts.py", line 271, in _iter
nocache
 hdr = next(it)
 File "C:\Jython\Lib\site-packages\petl\io\csv_py2.py", line 30, in __iter__
 codec = getcodec(self.encoding)
 File "C:\Jython\Lib\site-packages\petl\io\base.py", line 12, in getcodec
 codec = codecs.lookup(encoding)
 at org.python.core.codecs.normalizestring(codecs.java:62)
 at org.python.core.codecs.access200ドル(codecs.java:29)
 at org.python.core.codecs$CodecState.lookup(codecs.java:1695)
 at org.python.core.codecs.lookup(codecs.java:58)
 at org.python.modules._codecs.lookup(_codecs.java:57)
 at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
 at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.
java:57)
 at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAcces
sorImpl.java:43)
 at java.lang.reflect.Method.invoke(Method.java:601)
java.lang.NullPointerException: java.lang.NullPointerException

• jfs: Does it fail if you run it using a standalone jython executable instead of embedding it? Might be related: Unable to use the codecs module when embedding Jython
• Thavidu: Yes sir, it fails to run using a standalone jython executable too. But it runs when I run it as a standalone python. (With "python script.py" command)
• jfs: What is the output of jython -c "import codecs, sys; print codecs.lookup('utf8'), sys.path, sys.executable"?
• Thavidu: Output for the above command is: <codecs.CodecInfo object for encoding utf-8 at 0x2> ['', 'C:\\Jython\\Lib\\site- packages\\jip-0.9.4-py2.7.egg', 'C:\\Jython\\Lib\\site-packages\\requests-2.7.0- py2.7.egg', 'C:\\Jython\\Lib', 'classpath', '__pyclasspath__/', 'C:\\Jython\ \Lib\\site-packages'] C:\Jython\bin\jython.exe
• jfs: you should put the output in your question (to format it properly). Have you noticed that C:\Jython != C:\jython2.7.0? Use the right jython executable, run jython -c "import codecs; print codecs.lookup(None)". To workaround the issue, try to pass the encoding to tocsv() function explicitly (a string, not None).

Answer 1

You have to explicitly pass the value for encoding when calling both fromcsv() and tocsv() functions.

import petl as etl
table1 = etl.fromcsv(source='Books.csv',encoding='utf-8')
table2 = etl.sort(table1, 'ACCOUNT_ID')
etl.tocsv(table2, source='NewBooks.csv',encoding='utf-8')