[
https://issues.apache.org/jira/browse/NUTCH-2378?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
]
Jurian Broertjes updated NUTCH-2378:
------------------------------------
Attachment: NUTCH-2378-childfirst-plugin-classloader.patch
> ChildFirst plugin classloader
> -----------------------------
>
> Key: NUTCH-2378
> URL: https://issues.apache.org/jira/browse/NUTCH-2378
> Project: Nutch
> Issue Type: Improvement
> Affects Versions: 1.13
> Reporter: Jurian Broertjes
> Attachments: NUTCH-2378-childfirst-plugin-classloader.patch
>
>
> While working on upgrading the indexer-elastic plugin from 2.x to 5.x, I ran
> into several nasty runtime dependency issues (both local and on Hadoop).
> After seeking help on the mailing list, I still was unable to resolve these
> issues and after digging further, decided to try a different plugin
> classloader strategy.
> The normal classloader delegates class loading requests to it's parent
> classloader. This can cause all sorts of nasty runtime dependency version
> conflicts (jar hell, version conflicts), since the plugin's own classloader
> gets queried last. The child-first classloader approach tries to load a class
> from the plugin's dependencies first and when unavailable, delegates to it's
> parent classloader. This fixed the issues I had.
> The new approach can give runtime LinkageErrors, but these are easily
> resolvable (see the patch for a few examples)
> I've tested the new loader a bit and am curious about others' findings.
--
This message was sent by Atlassian JIRA
(v6.3.15#6346)
