Antony Stubbs created KAFKA-8884:
------------------------------------
Summary: Improve streams errors on class cast exception in
ProcessorsNodes
Key: KAFKA-8884
URL: https://issues.apache.org/jira/browse/KAFKA-8884
Project: Kafka
Issue Type: Improvement
Components: streams
Affects Versions: 2.3.1
Reporter: Antony Stubbs
If a processor causes a class cast exception, atm you get a bit of a cryptic
error if you're not used to them, and without a context sensitive suggestion as
to what could be wrong. Often these can be cause by missconfigured Serdes
(defaults).
As an example of the improvement over the case exception:
{{org.apache.kafka.streams.errors.StreamsException: Exception caught in
process. taskId=0_0, processor=KSTREAM-SOURCE-0000000000,
topic=streams-plaintext-input, partition=0, offset=0,
stacktrace=org.apache.kafka.streams.errors.StreamsException: A deserializer
(key: org.apache.kafka.common.serialization.ByteArrayDeserializer / value:
org.apache.kafka.common.serialization.ByteArrayDeserializer) is not compatible
to the actual key or value type (key type: [B / value type: [B). Change the
default Serdes in StreamConfig or provide correct Serdes via method
parameters.}}
{{ at
org.apache.kafka.streams.processor.internals.SourceNode.process(SourceNode.java:96)}}
{{ at
org.apache.kafka.streams.processor.internals.StreamTask.process(StreamTask.java:366)}}
{{ at
org.apache.kafka.streams.TopologyTestDriver.pipeInput(TopologyTestDriver.java:419)}}
{{ at
org.apache.kafka.streams.processor.internals.ProcessorNodeTest.testTopologyLevelClassCastException(ProcessorNodeTest.java:176)}}
{{ at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native
Method)}}
{{ at
java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)}}
{{ at
java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)}}
{{ at java.base/java.lang.reflect.Method.invoke(Method.java:566)}}
{{ at
org.junit.runners.model.FrameworkMethod$1.runReflectiveCall(FrameworkMethod.java:59)}}
{{ at
org.junit.internal.runners.model.ReflectiveCallable.run(ReflectiveCallable.java:12)}}
{{ at
org.junit.runners.model.FrameworkMethod.invokeExplosively(FrameworkMethod.java:56)}}
{{ at
org.junit.internal.runners.statements.InvokeMethod.evaluate(InvokeMethod.java:17)}}
{{ at org.junit.runners.ParentRunner$3.evaluate(ParentRunner.java:305)}}
{{ at
org.junit.runners.BlockJUnit4ClassRunner$1.evaluate(BlockJUnit4ClassRunner.java:100)}}
{{ at org.junit.runners.ParentRunner.runLeaf(ParentRunner.java:365)}}
{{ at
org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:103)}}
{{ at
org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:63)}}
{{ at org.junit.runners.ParentRunner$4.run(ParentRunner.java:330)}}
{{ at org.junit.runners.ParentRunner$1.schedule(ParentRunner.java:78)}}
{{ at org.junit.runners.ParentRunner.runChildren(ParentRunner.java:328)}}
{{ at org.junit.runners.ParentRunner.access$100(ParentRunner.java:65)}}
{{ at org.junit.runners.ParentRunner$2.evaluate(ParentRunner.java:292)}}
{{ at org.junit.runners.ParentRunner$3.evaluate(ParentRunner.java:305)}}
{{ at org.junit.runners.ParentRunner.run(ParentRunner.java:412)}}
{{ at org.junit.runner.JUnitCore.run(JUnitCore.java:137)}}
{{ at
com.intellij.junit4.JUnit4IdeaTestRunner.startRunnerWithArgs(JUnit4IdeaTestRunner.java:68)}}
{{ at
com.intellij.rt.execution.junit.IdeaTestRunner$Repeater.startRunnerWithArgs(IdeaTestRunner.java:47)}}
{{ at
com.intellij.rt.execution.junit.JUnitStarter.prepareStreamsAndStart(JUnitStarter.java:242)}}
{{ at com.intellij.rt.execution.junit.JUnitStarter.main(JUnitStarter.java:70)}}
{{Caused by: java.lang.ClassCastException: class [B cannot be cast to class
java.lang.String ([B and java.lang.String are in module java.base of loader
'bootstrap')}}
{{ at
org.apache.kafka.streams.kstream.internals.AbstractStream.lambda$withKey$1(AbstractStream.java:103)}}
{{ at
org.apache.kafka.streams.kstream.internals.KStreamFlatMapValues$KStreamFlatMapValuesProcessor.process(KStreamFlatMapValues.java:40)}}
{{ at
org.apache.kafka.streams.processor.internals.ProcessorNode.process(ProcessorNode.java:118)}}
{{ at
org.apache.kafka.streams.processor.internals.ProcessorContextImpl.forward(ProcessorContextImpl.java:201)}}
{{ at
org.apache.kafka.streams.processor.internals.ProcessorContextImpl.forward(ProcessorContextImpl.java:180)}}
{{ at
org.apache.kafka.streams.processor.internals.ProcessorContextImpl.forward(ProcessorContextImpl.java:133)}}
{{ at
org.apache.kafka.streams.processor.internals.SourceNode.process(SourceNode.java:89)}}
{{ ... 28 more}}
--
This message was sent by Atlassian Jira
(v8.3.2#803003)
