[kepler-dev] what's the deal with org.kepler.loader.InitClassPath?

Dan Higgins higgins at nceas.ucsb.edu
Wed Oct 29 12:21:40 PDT 2008

Hi David and Tristan,
    I am the culprit that initiated the InitClassPath idea (before I 
retired from NCEAS last Feb). It was far from an ideal solution (but a 
vast improvement over trying to keep a list of more than 100 jars 
up-to-date all the time).  Note that using ant was NOT considered a good 
idea at the time because we did not want to ship ant with Kepler, many 
novice users (not developers!) did not know what ant is, did not want to 
install it, and did not know how to use it. I encourage efforts to 
improve classpath handling but do suggest that developers try to hide 
the details from potential ordinary users.

Dan Higgins
NCEAS - (retired)

David Welker wrote:
> Hi Tristan,
> I agree with you that this InitClassPath idea was probably not a good 
> one. I know you have your own Maven build going on... but I should 
> point out that in the loader module used with the new build system, 
> InitClassPath is no longer used. If you are so inclined, you might 
> want to check out the new build system, especially the 1.1 branch. It 
> is, in my opinion, a vast improvement over the previous build system. 
> (Note: I am, of course, biased, since I have been the person who has 
> primarily developed the new build system.) But, perhaps more 
> importantly from your perspective, InitClassPath is not used, so this 
> problem you are having will no longer exist. As you suggest, in the 
> new build system, I use ant to manage the class path, and it does the 
> job.
> David
>> Hi Tristan,
>> I think this class is there so that the classpath can be amended to 
>> allow for different versions of the same class in different jars.  I 
>> think Dan Crawl last worked on it, so I'll let him explain more.  I 
>> think it's a bug that it finds files in the .svn directories.  They 
>> should probably be explicitly excluded from the search as we will 
>> never want anything in those directories in the classpath.
>> We have plans to overhaul this system sometime in the next year when 
>> we start re-architecting the core of kepler.
>> As for including all of jython in kepler, I don't have a problem with 
>> that as long as it isn't 20 MB of jar files or something huge like 
>> that.  We're in the process of breaking kepler up into modules which 
>> will be built by a single build system.  A Jython module would 
>> probably be a nice addition to kepler.  I'm hoping to have the new 
>> directory structure for the modules sorted out in the next week or so 
>> and I'm almost at a point where I can check in the changes that I've 
>> made to split the core of kepler away from other functionality.  
>> Needless to say, there are some pretty large changes coming to Kepler 
>> in the next couple weeks. You might want to wait just a bit until we 
>> get this new system in place before adding Jython.  We'll make an 
>> announcement to the community when everything is ready to go.
>> thanks,
>> chad
>> Tristan King wrote:
>>> I've been messing around with kepler's jython support recently 
>>> trying to get kepler to use my system's jython install rather than 
>>> the jython.jar included with kepler and run into an interesting 
>>> problem.
>>> The InitClassPath class recursively goes through the lib/jar/ 
>>> directory and adds anything it finds to the classpath. This includes 
>>> the .svn/**/*.jar.svn-base files. Thus, even if i overwrite the 
>>> lib/jar/jython.jar file, the 
>>> lib/jar/.svn/prop-base/jython.jar.svn-base file is found and added 
>>> to the classpath, and since . comes before j, the .svn/ version of 
>>> jython.jar takes precedence in the classpath. I haven't tested this, 
>>> but assume that this would effect any other files in the lib/jar/ 
>>> directory. If you try and update a library, you wont be able to test 
>>> it until you check the file into svn, which overwrites the stored 
>>> .svn version of the file.
>>> Is there any advantage to the InitClassPath class other than 
>>> removing the need to write out the classpath manually in release 
>>> builds? Because I can't see one, and I don't think the 
>>> aforementioned reason is a good reason for trying to build something 
>>> that ant provides already, and does right!
>>> -- 
>>> Tristan King
>>> Research Officer,
>>> eResearch Centre
>>> James Cook University, Townsville Qld 4811
>>> Australia
>>> Phone: +61747816902
>>> E-mail: tristan.king at jcu.edu.au <mailto:tristan.king at jcu.edu.au> 
>>> www: http://eresearch.jcu.edu.au
>>> ------------------------------------------------------------------------ 
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