[HDFS-8841] Catch throwable return null

• Type: Bug
• Status: Open
• Priority: Minor
• Resolution: Unresolved
• Target Version/s: 2.6.0, 2.7.0, 2.5.1, 2.5.2, 2.7.1
• Assignee: Unassigned
• Reporter: songwanging
• Created: 31/Jul/15 06:35
• Updated: 27/Aug/15 14:42

Description

In method "map" of class: \hadoop-2.7.1-src\hadoop-tools\hadoop-extras\src\main\java\org\apache\hadoop\tools\DistCpV1.java.

This method has this code:

public void map(LongWritable key,
FilePair value,
OutputCollector<WritableComparable<?>, Text> out,
Reporter reporter) throws IOException

{ ... }

catch (Throwable ex)

{ // ignore, we are just cleaning up LOG.debug("Ignoring cleanup exception", ex); }

....
}
}
...
}

Throwable is the parent type of Exception and Error, so catching Throwable means catching both Exceptions as well as Errors. An Exception is something you could recover (like IOException), an Error is something more serious and usually you could'nt recover easily (like ClassNotFoundError) so it doesn't make much sense to catch an Error.

We should convert to catch Exception instead.