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Posted to issues@flink.apache.org by "Tzu-Li (Gordon) Tai (JIRA)" <ji...@apache.org> on 2017/03/11 10:59:04 UTC
[jira] [Updated] (FLINK-6025) User code ClassLoader not used when
KryoSerializer fallbacks to serialization for copying
[ https://issues.apache.org/jira/browse/FLINK-6025?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]
Tzu-Li (Gordon) Tai updated FLINK-6025:
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Description:
Reported in ML: http://apache-flink-user-mailing-list-archive.2336050.n4.nabble.com/AWS-exception-serialization-problem-td12063.html
This is caused by a known Kryo issue with its {{JavaSerializer}}: https://github.com/EsotericSoftware/kryo/pull/483.
It happens when a {{Throwable}} is to be copied by the {{KryoSerialzer}}. Since we use the {{JavaSerializer}} for throwables, and {{JavaSerializer}} doesn't support copying, the {{KryoSerializer}} fallbacks to use de-/serialization for the throwable. The problem is that on deserialization, the classloader that the {{ObjectInputStream}} uses may be overriden, and doesn't specifically uses Kryo's configured classloader (i.e., the user code class loader), and results in {{ClassNotFoundException}}.
Generally, this may happen if the user also registers to use the {{JavaSerializer}} for their types.
To fix the problem for {{Throwable}} serializing in the {{KryoSerializer}}, we could either consider registering our own {{JavaSerializer}} that fixes this problem, or wait for the Kryo fix to be released (to be fixed in Kryo 4.0.1 release).
was:
Reported in ML: http://apache-flink-user-mailing-list-archive.2336050.n4.nabble.com/AWS-exception-serialization-problem-td12063.html
This is a known Kryo issue with its {{JavaSerializer}}: https://github.com/EsotericSoftware/kryo/pull/483.
It happens when a {{Throwable}} is to be copied by the {{KryoSerialzer}}. Since we use the {{JavaSerializer}} for throwables, and {{JavaSerializer}} doesn't support copying, the {{KryoSerializer}} fallbacks to use de-/serialization for the throwable. The problem is that on deserialization, the classloader that the {{ObjectInputStream}} uses may be overriden, and doesn't specifically uses Kryo's configured classloader (i.e., the user code class loader), and results in {{ClassNotFoundException}}.
Generally, this may happen if the user also registers to use the {{JavaSerializer}} for their types.
To fix the problem for {{Throwable}} serializing in the {{KryoSerializer}}, we could either consider registering our own {{JavaSerializer}} that fixes this problem, or wait for the Kryo fix to be released (to be fixed in Kryo 4.0.1 release).
> User code ClassLoader not used when KryoSerializer fallbacks to serialization for copying
> -----------------------------------------------------------------------------------------
>
> Key: FLINK-6025
> URL: https://issues.apache.org/jira/browse/FLINK-6025
> Project: Flink
> Issue Type: Bug
> Components: Type Serialization System
> Reporter: Tzu-Li (Gordon) Tai
>
> Reported in ML: http://apache-flink-user-mailing-list-archive.2336050.n4.nabble.com/AWS-exception-serialization-problem-td12063.html
> This is caused by a known Kryo issue with its {{JavaSerializer}}: https://github.com/EsotericSoftware/kryo/pull/483.
> It happens when a {{Throwable}} is to be copied by the {{KryoSerialzer}}. Since we use the {{JavaSerializer}} for throwables, and {{JavaSerializer}} doesn't support copying, the {{KryoSerializer}} fallbacks to use de-/serialization for the throwable. The problem is that on deserialization, the classloader that the {{ObjectInputStream}} uses may be overriden, and doesn't specifically uses Kryo's configured classloader (i.e., the user code class loader), and results in {{ClassNotFoundException}}.
> Generally, this may happen if the user also registers to use the {{JavaSerializer}} for their types.
> To fix the problem for {{Throwable}} serializing in the {{KryoSerializer}}, we could either consider registering our own {{JavaSerializer}} that fixes this problem, or wait for the Kryo fix to be released (to be fixed in Kryo 4.0.1 release).
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