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From "ChiaHung Lin (JIRA)" <j...@apache.org>
Subject [jira] [Commented] (HAMA-378) Lost connection to BSP Master [host/ip:port]. Retrying...
Date Wed, 27 Apr 2011 02:15:04 GMT

    [ https://issues.apache.org/jira/browse/HAMA-378?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13025568#comment-13025568
] 

ChiaHung Lin commented on HAMA-378:
-----------------------------------

The jar file exists on the groom server, but the file to be unpacked in the path is not a
correct one. 

>From what has been discovered, it looks like when executing findContainingJar() in BSPJob,
my_class.getClassLoader() would be different from what has been proposed in RunJar, in which
the context class loader is set to URLClassLoader. Also, the jar file in command e.g. `hama
jar path/to/eaxmple.jar` is added to classpath (if what perceived is correct). But in the
findContainingJar function, the context loader is not the one proposed i.e. URLClassLoader;
therefore, url.getProtocol() only returns `file' instead of `jar', resulting the execution
of findContaingJar function returns null. Thus, bsp.jar is not set in configuration. 

This is just what is discovered, but it might be a red herring and a further investigation
may be required. 




> Lost connection to BSP Master [host/ip:port].  Retrying... 
> -----------------------------------------------------------
>
>                 Key: HAMA-378
>                 URL: https://issues.apache.org/jira/browse/HAMA-378
>             Project: Hama
>          Issue Type: Improvement
>          Components: bsp
>            Reporter: ChiaHung Lin
>            Priority: Minor
>
> When submitting a job, at the server side the GroomServer reports message
>     Lost connection to BSP Master [host/ip:port].  Retrying... java.lang.NullPointerException
> This seems because the script hama only includes jar files (such as hama-0.3.0-examples.jar)
located under basedir, the same folder as build.xml. Also, a quick check shows that when submitting
a job, the ClassLader used is sun.misc.Launcher$AppClassLoader, instead of java.net.URLClassLoader.
This might not be the root cause, but a further investigation may be required. 

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