Re: [gentoo-java] java 5 classpath policy?

[Vincent Schut <schut@sarvision.nl>]

Joshua Nichols wrote:

>Vincent Schut wrote:
>  
>
>>Hi all,
>>
>>when using java-config-2 from migration-overlay, it says 'deprecated'
>>for all classpath related functions. I tried to find some more info on
>>this, but couldn't find it. Maybe someone here can elaborate a bit more
>>on how to work with java classpath (system and user) in the new gentoo
>>java system? E.g. if I want to have some packages in my classpath, how
>>would I do that using the new system? And how is this working
>>together/conflicting with the current (old) items in /etc/env.d/ ?
>>
>>Cheers,
>>Vincent.
>>  
>>    
>>
>
>Setting a user and system wide classpath is deprecated because it can
>cause several issues.
>
>For example, say you put the classes from foo-2.0 on your classpath.
>Then you emerge something that uses foo-1.0. This would because foo
>would be slotted. However, when the build takes place, foo-2.0 could be
>on the classpath before foo-1.0. It may have the same classnames and
>whatnot, but different API. The differences between the APIs could then
>cause the build to fail.
>
>Similarly, this scenario may also occur while running an application.
>foo-1.0 might be expected, but foo-2.0 is on the classpath first... so
>it may be missing methods, or have different behavior, and so on.
>
>
>As for what to do instead of setting the classpath, it depends on what
>you're trying to do. If you have an application that needs a certain
>thing on the classpath, it is best to have a launcher script which sets
>the right CLASSPATH. If you're building something that needs a
>particular library, you should make the something be explicitly aware of
>what it needs. In ant, this could mean having a lib directory with all
>the jars (or symlinks to them), then you create a <path> that all your
><javac> and <java>'s use. This would really be dependent on how you're
>building your project.
>
>This problem, and workarounds for it, are in the updated user
>documentation
>(https://svn.gentooexperimental.org/svn/java/migration/docs/java-user.html).
>
>Hope this clarifies,
>  
>
It sure does. Thanks.

Vincent.

>Josh
>  
>

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