Fix exception handling for JPype 0.7

[baztian]

thanks @Thrameos for pointing out the issue (#102)

[baztian]

@Thrameos you mentioned some exception handling changes in #102. I don't really get how it changed. Also it's been a while back I wrote the exception handling code.
Can you please give me some advice on how to change the code accordingly?

[Thrameos]

Should be covered in jpype-project/jpype#498 and pyathena-dev/PyAthenaJDBC#85

The original exception code caught a dummy class that held the real exception as the first argument but the version directly throws the exception. There was a common pattern that both versions are supposed to be able to use using JException, but thus far I have seen a lot of code that get into the arguments.

Hopefully these two threads have enough to help. If not just reply an I will take a deeper look at your structure.

[baztian]

Thanks @Thrameos. I tried two different approaches to deal with exceptions in this PR. Looking deeper into it it seems I'm (now) catching the exceptions correctly. But the unit test uses str/toString on the exception and is getting the wrong output. The code works with the older JPypes and with Jython.

The output of the test can be found in the travis job output.

It seems to be a JPype 0.7 shortcomming. Can you please have another look on this?

[baztian]

One other thing in JPype 0.7 I don't really get is that string conversion seems to be changed for non Pyhton 3 versions. https://travis-ci.org/baztian/jaydebeapi/jobs/556477652#L286 works with the old JPype version: https://travis-ci.org/baztian/jaydebeapi/jobs/556477652#L498
@Thrameos any ideas?

[Thrameos]

Well str(exception) should be calling exception.toString() which should be what you expect. It looks like there may be a bug in jpype with this regard.

Seems like the line 65 in jpype/_jexception.py

     def __str__(self):
        return str(self.getMessage())

should read as

     def __str__(self):
        return str(self.toString())

[Thrameos]

As to the other question, are you referring to string conversions in general such as returning java.lang.String rather than Python strings or something else?

[baztian]

I'm going to ignore that issue with 0.7.0 and test against 0.7.1. #151 will fix the build