Re: Is there a better way to debug ClassNotFoundException from FlinkUserCodeClassLoaders?

Thu, 03 Jan 2019 01:08:29 -0800 

Hi Hao,
which Flink version are you using? What do you mean with "suddenly", did it work before? 

Regards,
Timo


Am 03.01.19 um 07:13 schrieb Hao Sun:

Yep, javap shows the class is there, but FlinkUserCodeClassLoaders 
somehow could not find it suddenly



javap -cp /opt/flink/lib/zendesk-fps-core-assembly-0.1.0.jar 
'com.zendesk.fraudprevention.examples.ConnectedStreams$$anon$90$$anon$45'

Compiled from "ConnectedStreams.scala"

public final class 
com.zendesk.fraudprevention.examples.ConnectedStreams$$anon$90$$anon$45 
extends 
org.apache.flink.api.scala.typeutils.CaseClassSerializer<com.zendesk.fraudprevention.datatypes.MaxwellEvent> 
{
public com.zendesk.fraudprevention.datatypes.MaxwellEvent 
createInstance(java.lang.Object[]);
public 
org.apache.flink.api.scala.typeutils.CaseClassSerializer<com.zendesk.fraudprevention.datatypes.MaxwellEvent> 
createSerializerInstance(java.lang.Class<com.zendesk.fraudprevention.datatypes.MaxwellEvent>, 
org.apache.flink.api.common.typeutils.TypeSerializer<?>[]);
public org.apache.flink.api.java.typeutils.runtime.TupleSerializerBase 
createSerializerInstance(java.lang.Class, 
org.apache.flink.api.common.typeutils.TypeSerializer[]);

public java.lang.Object createInstance(java.lang.Object[]);

public 
com.zendesk.fraudprevention.examples.ConnectedStreams$$anon$90$$anon$45(com.zendesk.fraudprevention.examples.ConnectedStreams$$anon$90, 
org.apache.flink.api.common.typeutils.TypeSerializer[]);

}

Hao Sun
Team Lead
1019 Market St. 7F
San Francisco, CA 94103



On Wed, Jan 2, 2019 at 6:04 PM qi luo <luoqi...@gmail.com 
<mailto:luoqi...@gmail.com>> wrote:


    Hi Hao,

    Since Flink is using Child-First class loader, you may try search
    for the class
    "*com.zendesk.fraudprevention.examples.ConnectedStreams$$anon$90$$anon$45”
    in your fat JAR. Is that an inner class?*
    *
    *
    *Best,*
    *Qi*


    On Jan 3, 2019, at 7:01 AM, Hao Sun <ha...@zendesk.com
    <mailto:ha...@zendesk.com>> wrote:

    Hi,

    I am wondering if there are any protips to figure out what class
    is not found?

    ===== Logs ====
    org.apache.flink.streaming.runtime.tasks.StreamTaskException:
    Could not instantiate chained outputs.
    at
    
org.apache.flink.streaming.api.graph.StreamConfig.getChainedOutputs(StreamConfig.java:324)
    at
    
org.apache.flink.streaming.runtime.tasks.OperatorChain.createOutputCollector(OperatorChain.java:292)
    at
    
org.apache.flink.streaming.runtime.tasks.OperatorChain.<init>(http://OperatorChain.java:133)
    at
    
org.apache.flink.streaming.runtime.tasks.StreamTask.invoke(StreamTask.java:267)
    at org.apache.flink.runtime.taskmanager.Task.run(Task.java:704)
    at java.lang.Thread.run(Thread.java:748)
    *Caused by: java.lang.ClassNotFoundException:
    com.zendesk.fraudprevention.examples.ConnectedStreams$$anon$90$$anon$45*
    at java.net.URLClassLoader.findClass(URLClassLoader.java:381)
    at java.lang.ClassLoader.loadClass(ClassLoader.java:424)
    at
    
org.apache.flink.runtime.execution.librarycache.FlinkUserCodeClassLoaders$ChildFirstClassLoader.loadClass(FlinkUserCodeClassLoaders.java:129)
    at java.lang.ClassLoader.loadClass(ClassLoader.java:357)
    at java.lang.Class.forName0(Native Method)
    at java.lang.Class.forName(Class.java:348)
    at
    
org.apache.flink.util.InstantiationUtil$ClassLoaderObjectInputStream.resolveClass(InstantiationUtil.java:77)
    at
    java.io.ObjectInputStream.readNonProxyDesc(ObjectInputStream.java:1866)
    at
    java.io.ObjectInputStream.readClassDesc(ObjectInputStream.java:1749)
    at
    java.io.ObjectInputStream.readOrdinaryObject(ObjectInputStream.java:2040)
    at java.io.ObjectInputStream.readObject0(ObjectInputStream.java:1571)
    at
    java.io.ObjectInputStream.defaultReadFields(ObjectInputStream.java:2285)
    at
    java.io.ObjectInputStream.readSerialData(ObjectInputStream.java:2209)
    at
    java.io.ObjectInputStream.readOrdinaryObject(ObjectInputStream.java:2067)
    at java.io.ObjectInputStream.readObject0(ObjectInputStream.java:1571)
    at
    java.io.ObjectInputStream.defaultReadFields(ObjectInputStream.java:2285)
    at
    java.io.ObjectInputStream.readSerialData(ObjectInputStream.java:2209)
    at
    java.io.ObjectInputStream.readOrdinaryObject(ObjectInputStream.java:2067)
    at java.io.ObjectInputStream.readObject0(ObjectInputStream.java:1571)
    at java.io.ObjectInputStream.readObject(ObjectInputStream.java:431)
    at java.util.ArrayList.readObject(ArrayList.java:797)
    at sun.reflect.GeneratedMethodAccessor26.invoke(Unknown Source)
    at
    
sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.lang.reflect.Method.invoke(Method.java:498)
    at
    java.io.ObjectStreamClass.invokeReadObject(ObjectStreamClass.java:1158)
    at
    java.io.ObjectInputStream.readSerialData(ObjectInputStream.java:2176)
    at
    java.io.ObjectInputStream.readOrdinaryObject(ObjectInputStream.java:2067)
    at java.io.ObjectInputStream.readObject0(ObjectInputStream.java:1571)
    at java.io.ObjectInputStream.readObject(ObjectInputStream.java:431)
    at
    
org.apache.flink.util.InstantiationUtil.deserializeObject(InstantiationUtil.java:524)
    at
    
org.apache.flink.util.InstantiationUtil.deserializeObject(InstantiationUtil.java:510)
    at
    
org.apache.flink.util.InstantiationUtil.deserializeObject(InstantiationUtil.java:498)
    at
    
org.apache.flink.util.InstantiationUtil.readObjectFromConfig(InstantiationUtil.java:459)
    at
    
org.apache.flink.streaming.api.graph.StreamConfig.getChainedOutputs(StreamConfig.java:321)
    ... 5 more


    Hao Sun
    Team Lead
    1019 Market St. 7F
    San Francisco, CA 94103


























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