fix issue https://issues.apache.org/jira/browse/FLINK-12725

[arganzheng]

What is the purpose of the change

fix issue https://issues.apache.org/jira/browse/FLINK-12725. No need to copy the flink-hadoop-compatibility jar explicitly to ${FLINK-HOME}/lib location.

Brief change log

change the classLoader of org.apache.flink.api.java.typeutils.WritableTypeInfo from TypeExtractor.class.getClassLoader() to Thread.currentThread().getContextClassLoader().

Verifying this change

This change is a trivial rework / code cleanup without any test coverage.

Does this pull request potentially affect one of the following parts:

• Dependencies (does it add or upgrade a dependency): (no)
• The public API, i.e., is any changed class annotated with @Public(Evolving): ( no)
• The serializers: (no)
• The runtime per-record code paths (performance sensitive): (no/)
• Anything that affects deployment or recovery: JobManager (and its components), Checkpointing, Yarn/Mesos, ZooKeeper: (no)
• The S3 file system connector: (no)

Documentation

• Does this pull request introduce a new feature? (no)

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[arganzheng]

@aljoscha Here

[dawidwys]

Hi @arganzheng,
Thank you for your contribution. Could you please update the subject of this PR according to the contribution guidelines?

[aljoscha]

Thanks! I merged this already. For next time, please provide a good title for the PR according to the contribution guidelines, as Dawid mentioned.

[arganzheng]

Sorry for the title, I did not read the guidelines carefully.

[ben-wangz]

i cherry-pick this fix to release-1.8.0 and run it with mongo input format (org.mongodb, mongo-hadoop-core, 1.3.0)。 found exception of java.lang.LinkageError:

Caused by: java.lang.LinkageError: loader constraint violation: when resolving method "com.esotericsoftware.kryo.Kryo$DefaultInstantiatorStrategy.setFallbackInstantiatorStrategy(Lorg/objenesis/strategy/InstantiatorStrategy;)V" the class loader (instance of org/apache/flink/runtime/execution/librarycache/FlinkUserCodeClassLoaders$ChildFirstClassLoader) of the current class, org/apache/flink/api/java/typeutils/runtime/WritableSerializer, and the class loader (instance of sun/misc/Launcher$AppClassLoader) for the method's defining class, com/esotericsoftware/kryo/Kryo$DefaultInstantiatorStrategy, have different Class objects for the type org/objenesis/strategy/InstantiatorStrategy used in the signature
        at org.apache.flink.api.java.typeutils.runtime.WritableSerializer.checkKryoInitialized(WritableSerializer.java:131)
        at org.apache.flink.api.java.typeutils.runtime.WritableSerializer.copy(WritableSerializer.java:68)
        at org.apache.flink.api.java.typeutils.runtime.WritableSerializer.copy(WritableSerializer.java:42)
        at org.apache.flink.api.java.typeutils.runtime.TupleSerializer.copy(TupleSerializer.java:111)
        at org.apache.flink.api.java.typeutils.runtime.TupleSerializer.copy(TupleSerializer.java:37)
        at org.apache.flink.streaming.runtime.tasks.OperatorChain$CopyingChainingOutput.pushToOperator(OperatorChain.java:577)
        at org.apache.flink.streaming.runtime.tasks.OperatorChain$CopyingChainingOutput.collect(OperatorChain.java:554)
        at org.apache.flink.streaming.runtime.tasks.OperatorChain$CopyingChainingOutput.collect(OperatorChain.java:534)
        at org.apache.flink.streaming.api.operators.AbstractStreamOperator$CountingOutput.collect(AbstractStreamOperator.java:718)
        at org.apache.flink.streaming.api.operators.AbstractStreamOperator$CountingOutput.collect(AbstractStreamOperator.java:696)
        at org.apache.flink.streaming.api.operators.StreamSourceContexts$NonTimestampContext.collect(StreamSourceContexts.java:104)
        at org.apache.flink.streaming.api.functions.source.InputFormatSourceFunction.run(InputFormatSourceFunction.java:93)
        at org.apache.flink.streaming.api.operators.StreamSource.run(StreamSource.java:93)
        at org.apache.flink.streaming.api.operators.StreamSource.run(StreamSource.java:57)
        at org.apache.flink.streaming.runtime.tasks.SourceStreamTask.run(SourceStreamTask.java:97)
        at org.apache.flink.streaming.runtime.tasks.StreamTask.invoke(StreamTask.java:300)
        at org.apache.flink.runtime.taskmanager.Task.run(Task.java:711)
        at java.lang.Thread.run(Thread.java:745)

[HenryCaiHaiying]

@ben-wangz I have the same issue on flink 1.9.1: how did you work around it?

Caused by: java.lang.LinkageError: loader constraint violation: when resolving method "com.esotericsoftware.kryo.Kryo$DefaultInstantiatorStrategy.setFallbackInstantiatorStrategy(Lorg/objenesis/strategy/InstantiatorStrategy;)V" the class loader (instance of org/apache/flink/runtime/execution/librarycache/FlinkUserCodeClassLoaders$ChildFirstClassLoader) of the current class, org/apache/flink/api/java/typeutils/runtime/WritableSerializer, and the class loader (instance of sun/misc/Launcher$AppClassLoader) for the method's defining class, com/esotericsoftware/kryo/Kryo$DefaultInstantiatorStrategy, have different Class objects for the type org/objenesis/strategy/InstantiatorStrategy used in the signature

[gwshawsh]

@HenryCaiHaiying flink-conf.yml ->classloader.resolve-order: parent-first