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https://issues.apache.org/jira/browse/FLINK-5854?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15874933#comment-15874933
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ASF GitHub Bot commented on FLINK-5854:
---------------------------------------
Github user StephanEwen commented on the issue:
https://github.com/apache/flink/pull/3368
@zentol There are many places in the runtime that declare `throws
Exception`, for example virtually all of the state handling code. This always
came from the desire to throw `IOException` plus something that expresses that
non-I/O stuff related to Flink went wrong. The result was a `throws Exception`,
which also means that you have to catch `Exception` which you often don't want
(because this included `RuntimeException` and you typically want runtime
exception to bubble up a bit further, since they denote bugs by encouraged
design).
The only place where `throws Exception` really makes sense to me is for
`MapFunction` and the likes, to allow them to propagate any type of exception
and let recovery handle them.
> Introduce some Flink-specific base Exception types
> --------------------------------------------------
>
> Key: FLINK-5854
> URL: https://issues.apache.org/jira/browse/FLINK-5854
> Project: Flink
> Issue Type: Improvement
> Components: Core
> Reporter: Stephan Ewen
> Assignee: Stephan Ewen
> Fix For: 1.3.0
>
>
> Going through the code, there are a lot of places where exception handling
> could be done a bit nicer, for example
> - Some methods do not declare exceptions at all in their signatures. They
> simply catch all and wrap it in a {{RuntimeException}}.
> - Some places declare overly generic that they throw {{Exception}}, even
> though they could very specifically type the exceptions they throw.
> I suggest to introduce two new basic exceptions, that at least help document
> a bit more what goes wrong:
> - {{FlinkException}} as a base class for checked exceptions that indicate
> that something related to using Flink went wrong. Letting a method throw
> {{FlinkException}} rather than {{Exception}} already helps to not include all
> of Java's runtime exceptions, which indicate programming errors, rather than
> situations that should be recovered.
> - {{FlinkUncheckedException}} as a Flink-specific subclass of
> {{RuntimeException}}. That one can come in handy in places where no
> exceptions were declared, for example when reusing an interface that does not
> declare exceptions.
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