Issue1585

Jython behaves differently that Python does in this respect:

C:\Dokumente und Einstellungen\aek>\Programme\Python2.6\python.exe
Python 2.6.4 (r264:75708, Oct 26 2009, 08:23:19) [MSC v.1500 32 bit (Intel)] on win32
Type "help", "copyright", "credits" or "license" for more information.
>>> try:
...     raise Exception(u'Flie\xdftext')
... except Exception, e:
...     print e
...
Traceback (most recent call last):
  File "<stdin>", line 4, in <module>
UnicodeEncodeError: 'ascii' codec can't encode character u'\xdf' in position 4: ordinal not in range(128)
>>> try:
...     raise Exception(u'Flie\xdftext')
... except Exception, e:
...     print unicode(e)
...
Fließtext
>>>
>>> ^Z


C:\Dokumente und Einstellungen\aek>\Programme\jython2.5.1\jython.bat
Jython 2.5.1 (Release_2_5_1:6813, Sep 26 2009, 13:47:54)
[Java HotSpot(TM) Client VM (Sun Microsystems Inc.)] on java1.6.0_15
Type "help", "copyright", "credits" or "license" for more information.
>>> try:
...     raise Exception(u'Flie\xdftext')
... except Exception, e:
...     print e
...
Traceback (most recent call last):
  File "<stdin>", line 4, in <module>
UnicodeEncodeError: 'ascii' codec can't encode character u'\xdf' in position 4: ordinal not in range(128)
>>> try:
...     raise Exception(u'Flie\xdftext')
... except Exception, e:
...     print unicode(e)
...
Traceback (most recent call last):
  File "<stdin>", line 4, in <module>
UnicodeEncodeError: 'ascii' codec can't encode character u'\xdf' in position 4: ordinal not in range(128)
>>>

This is probably the easiest way to reproduce this:
>>> unicode(Exception(u'\xe4'))
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
UnicodeEncodeError: 'ascii' codec can't encode character u'\xe4' in position 0: ordinal not in range(128)

Interestingly this works:
>>> unicode(Exception(u'\xe4').args[0])
u'\xe4'

I used Jython 2.5.1 to test this. With Python 2.6.2 both of the above examples return u'\xe4' as expected.

We match CPython 2.5 behavior, this changed in 2.6

Philip is definitely right:

Python 2.5.4 (r254:67916, Jan 20 2010, 21:44:03) 
[GCC 4.3.3] on linux2
Type "help", "copyright", "credits" or "license" for more information.
>>> unicode(Exception(u'\xe4'))
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
UnicodeEncodeError: 'ascii' codec can't encode character u'\xe4' in position 0: ordinal not in range(128)
>>> unicode(Exception(u'\xe4').args[0])
u'\xe4'