Re: Null Pointer Exception on Trying to read a message from Kafka

[Sridhar Chellappa]

OK. I got past the problem. Basically, I had to change

public class MyKafkaMessageSerDeSchema implements
DeserializationSchema,
SerializationSchema {

@Override
public MyKafkaMessage deserialize(byte[] message) throws IOException {
MyKafkaMessage MyKafkaMessage = null;
try {
MyKafkaMessage =  MyKafkaMessage.parseFrom(message);
} catch (InvalidProtocolBufferException e) {
e.printStackTrace();
} finally {
return MyKafkaMessage;
}
}

@Override
public boolean isEndOfStream(MyKafkaMessage nextElement) {
return false;
}

@Override
public TypeInformation getProducedType() {
return TypeExtractor.getForClass(MyKafkaMessage.class);;
-> Add Type Info
}

@Override
public byte[] serialize(MyKafkaMessage element) {
return
element.byteArray();
--> modify serializer
}
}


When I run my program, I get another exception :


java.lang.NullPointerException
at 
shaded.com.google.protobuf.UnmodifiableLazyStringList.size(UnmodifiableLazyStringList.java:68)
at java.util.AbstractList.add(AbstractList.java:108)
at 
com.esotericsoftware.kryo.serializers.CollectionSerializer.copy(CollectionSerializer.java:131)
at 
com.esotericsoftware.kryo.serializers.CollectionSerializer.copy(CollectionSerializer.java:22)
at com.esotericsoftware.kryo.Kryo.copy(Kryo.java:862)
at 
org.apache.flink.api.java.typeutils.runtime.kryo.KryoSerializer.copy(KryoSerializer.java:176)
at 
org.apache.flink.api.java.typeutils.runtime.PojoSerializer.copy(PojoSerializer.java:236)
at 
org.apache.flink.streaming.runtime.tasks.OperatorChain$CopyingChainingOutput.pushToOperator(OperatorChain.java:526)
at 
org.apache.flink.streaming.runtime.tasks.OperatorChain$CopyingChainingOutput.collect(OperatorChain.java:503)
at 
org.apache.flink.streaming.runtime.tasks.OperatorChain$CopyingChainingOutput.collect(OperatorChain.java:483)
at 
org.apache.flink.streaming.api.operators.AbstractStreamOperator$CountingOutput.collect(AbstractStreamOperator.java:891)
at 
org.apache.flink.streaming.api.operators.AbstractStreamOperator$CountingOutput.collect(AbstractStreamOperator.java:869)
at 
org.apache.flink.streaming.api.operators.StreamMap.processElement(StreamMap.java:41)
at 
org.apache.flink.streaming.runtime.tasks.OperatorChain$CopyingChainingOutput.pushToOperator(OperatorChain.java:528)
at 
org.apache.flink.streaming.runtime.tasks.OperatorChain$CopyingChainingOutput.collect(OperatorChain.java:503)
at 
org.apache.flink.streaming.runtime.tasks.OperatorChain$CopyingChainingOutput.collect(OperatorChain.java:483)
at 
org.apache.flink.streaming.api.operators.AbstractStreamOperator$CountingOutput.collect(AbstractStreamOperator.java:891)
at 
org.apache.flink.streaming.api.operators.AbstractStreamOperator$CountingOutput.collect(AbstractStreamOperator.java:869)
at 
org.apache.flink.streaming.api.operators.StreamSourceContexts$NonTimestampContext.collect(StreamSourceContexts.java:103)
at 
org.apache.flink.streaming.api.operators.StreamSourceContexts$NonTimestampContext.collectWithTimestamp(StreamSourceContexts.java:110)
at 
org.apache.flink.streaming.connectors.kafka.internals.AbstractFetcher.emitRecordWithTimestamp(AbstractFetcher.java:264)
at 
org.apache.flink.streaming.connectors.kafka.internal.Kafka010Fetcher.emitRecord(Kafka010Fetcher.java:86)
at 
org.apache.flink.streaming.connectors.kafka.internal.Kafka09Fetcher.runFetchLoop(Kafka09Fetcher.java:149)
at 
org.apache.flink.streaming.connectors.kafka.FlinkKafkaConsumerBase.run(FlinkKafkaConsumerBase.java:449)
at 
org.apache.flink.streaming.api.operators.StreamSource.run(StreamSource.java:87)
at 
org.apache.flink.streaming.api.operators.StreamSource.run(StreamSource.java:55)
at 
org.apache.flink.streaming.runtime.tasks.SourceStreamTask.run(SourceStreamTask.java:95)
at 
org.apache.flink.streaming.runtime.tasks.StreamTask.invoke(StreamTask.java:262)
at org.apache.flink.runtime.taskmanager.Task.run(Task.java:702)
at java.lang.Thread.run(Thread.java:748)


On Tue, Aug 29, 2017 at 8:43 AM, Ted Yu  wrote:

> The NPE came from this line:
>
> StreamRecord copy = castRecord.copy(serializer.
> copy(castRecord.getValue()));
>
> Either serializer or castRecord was null.
>
> I wonder if this has been fixed in 1.3.2 release.
>
> On Mon, Aug 28, 2017 at 7:24 PM, Sridhar Chellappa 
> wrote:
>
>> Kafka Version is 0.10.0
>>
>> On Tue, Aug 29, 2017 at 6:43 AM, Sridhar Chellappa 
>> wrote:
>>
>>> 1.3.0
>>>
>>> On Mon, Aug 28, 2017 at 10:09 PM, Ted Yu  wrote:
>>>
 Which Flink version are you using (so that line numbers can be matched
 

Re: Null Pointer Exception on Trying to read a message from Kafka

[Ted Yu]

The NPE came from this line:

StreamRecord copy =
castRecord.copy(serializer.copy(castRecord.getValue()));

Either serializer or castRecord was null.

I wonder if this has been fixed in 1.3.2 release.

On Mon, Aug 28, 2017 at 7:24 PM, Sridhar Chellappa 
wrote:

> Kafka Version is 0.10.0
>
> On Tue, Aug 29, 2017 at 6:43 AM, Sridhar Chellappa 
> wrote:
>
>> 1.3.0
>>
>> On Mon, Aug 28, 2017 at 10:09 PM, Ted Yu  wrote:
>>
>>> Which Flink version are you using (so that line numbers can be matched
>>> with source code) ?
>>>
>>> On Mon, Aug 28, 2017 at 9:16 AM, Sridhar Chellappa >> > wrote:
>>>
 DataStream MyKafkaMessageDataStream = env.addSource(
 getStreamSource(env, parameterTool);
 );



 public RichParallelSourceFunction
 getStreamSource(StreamExecutionEnvironment env, ParameterTool
 parameterTool) {

// MyKAfkaMessage is a ProtoBuf message
 env.getConfig().registerTypeWi
 thKryoSerializer(MyKafkaMessage.class, ProtobufSerializer.class);

 KafkaDataSource flinkCepConsumer =
 new KafkaDataSource(parameterTool,
 new MyKafkaMessageSerDeSchema());

 return flinkCepConsumer;
 }


 public class KafkaDataSource extends FlinkKafkaConsumer010 {

 public KafkaDataSource(ParameterTool parameterTool,
 DeserializationSchema deserializer) {
 super(
 Arrays.asList(parameterTool.ge
 tRequired("topic").split(",")),
 deserializer,
 parameterTool.getProperties()
 );

 }

 }

 public class MyKafkaMessageSerDeSchema implements
 DeserializationSchema, SerializationSchema
 {

 @Override
 public MyKafkaMessage deserialize(byte[] message) throws
 IOException {
 MyKafkaMessage MyKafkaMessage = null;
 try {
 MyKafkaMessage =  MyKafkaMessage.parseFrom(message);
 } catch (InvalidProtocolBufferException e) {
 e.printStackTrace();
 } finally {
 return MyKafkaMessage;
 }
 }

 @Override
 public boolean isEndOfStream(MyKafkaMessage nextElement) {
 return false;
 }

 @Override
 public TypeInformation getProducedType() {
 return null;
 }

 @Override
 public byte[] serialize(MyKafkaMessage element) {
 return new byte[0];
 }
 }

 On Mon, Aug 28, 2017 at 8:26 PM, Ted Yu  wrote:

> Which version of Flink / Kafka are you using ?
>
> Can you show the snippet of code where you create the DataStream ?
>
> Cheers
>
> On Mon, Aug 28, 2017 at 7:38 AM, Sridhar Chellappa <
> flinken...@gmail.com> wrote:
>
>> Folks,
>>
>> I have a KafkaConsumer that I am trying to read messages from. When I
>> try to create a DataStream from the KafkConsumer (env.addSource()) I get
>> the following exception :
>>
>> Any idea on how can this happen?
>>
>> java.lang.NullPointerException
>>  at 
>> org.apache.flink.streaming.runtime.tasks.OperatorChain$CopyingChainingOutput.pushToOperator(OperatorChain.java:526)
>>  at 
>> org.apache.flink.streaming.runtime.tasks.OperatorChain$CopyingChainingOutput.collect(OperatorChain.java:503)
>>  at 
>> org.apache.flink.streaming.runtime.tasks.OperatorChain$CopyingChainingOutput.collect(OperatorChain.java:483)
>>  at 
>> org.apache.flink.streaming.api.operators.AbstractStreamOperator$CountingOutput.collect(AbstractStreamOperator.java:891)
>>  at 
>> org.apache.flink.streaming.api.operators.AbstractStreamOperator$CountingOutput.collect(AbstractStreamOperator.java:869)
>>  at 
>> org.apache.flink.streaming.api.operators.StreamSourceContexts$NonTimestampContext.collect(StreamSourceContexts.java:103)
>>  at 
>> org.apache.flink.streaming.api.operators.StreamSourceContexts$NonTimestampContext.collectWithTimestamp(StreamSourceContexts.java:110)
>>  at 
>> org.apache.flink.streaming.connectors.kafka.internals.AbstractFetcher.emitRecordWithTimestamp(AbstractFetcher.java:264)
>>  at 
>> org.apache.flink.streaming.connectors.kafka.internal.Kafka010Fetcher.emitRecord(Kafka010Fetcher.java:86)
>>  at 
>> org.apache.flink.streaming.connectors.kafka.internal.Kafka09Fetcher.runFetchLoop(Kafka09Fetcher.java:149)
>>  at 
>> org.apache.flink.streaming.connectors.kafka.FlinkKafkaConsumerBase.run(FlinkKafkaConsumerBase.java:449)
>>  at 
>> org.apache.flink.streaming.api.operators.StreamSource.run(StreamSource.java:87)
>>  at 
>> 

Re: Null Pointer Exception on Trying to read a message from Kafka

[Sridhar Chellappa]

Kafka Version is 0.10.0

On Tue, Aug 29, 2017 at 6:43 AM, Sridhar Chellappa 
wrote:

> 1.3.0
>
> On Mon, Aug 28, 2017 at 10:09 PM, Ted Yu  wrote:
>
>> Which Flink version are you using (so that line numbers can be matched
>> with source code) ?
>>
>> On Mon, Aug 28, 2017 at 9:16 AM, Sridhar Chellappa 
>> wrote:
>>
>>> DataStream MyKafkaMessageDataStream = env.addSource(
>>> getStreamSource(env, parameterTool);
>>> );
>>>
>>>
>>>
>>> public RichParallelSourceFunction
>>> getStreamSource(StreamExecutionEnvironment env, ParameterTool
>>> parameterTool) {
>>>
>>>// MyKAfkaMessage is a ProtoBuf message
>>> 
>>> env.getConfig().registerTypeWithKryoSerializer(MyKafkaMessage.class,
>>> ProtobufSerializer.class);
>>>
>>> KafkaDataSource flinkCepConsumer =
>>> new KafkaDataSource(parameterTool,
>>> new MyKafkaMessageSerDeSchema());
>>>
>>> return flinkCepConsumer;
>>> }
>>>
>>>
>>> public class KafkaDataSource extends FlinkKafkaConsumer010 {
>>>
>>> public KafkaDataSource(ParameterTool parameterTool,
>>> DeserializationSchema deserializer) {
>>> super(
>>> Arrays.asList(parameterTool.ge
>>> tRequired("topic").split(",")),
>>> deserializer,
>>> parameterTool.getProperties()
>>> );
>>>
>>> }
>>>
>>> }
>>>
>>> public class MyKafkaMessageSerDeSchema implements
>>> DeserializationSchema, SerializationSchema
>>> {
>>>
>>> @Override
>>> public MyKafkaMessage deserialize(byte[] message) throws IOException
>>> {
>>> MyKafkaMessage MyKafkaMessage = null;
>>> try {
>>> MyKafkaMessage =  MyKafkaMessage.parseFrom(message);
>>> } catch (InvalidProtocolBufferException e) {
>>> e.printStackTrace();
>>> } finally {
>>> return MyKafkaMessage;
>>> }
>>> }
>>>
>>> @Override
>>> public boolean isEndOfStream(MyKafkaMessage nextElement) {
>>> return false;
>>> }
>>>
>>> @Override
>>> public TypeInformation getProducedType() {
>>> return null;
>>> }
>>>
>>> @Override
>>> public byte[] serialize(MyKafkaMessage element) {
>>> return new byte[0];
>>> }
>>> }
>>>
>>> On Mon, Aug 28, 2017 at 8:26 PM, Ted Yu  wrote:
>>>
 Which version of Flink / Kafka are you using ?

 Can you show the snippet of code where you create the DataStream ?

 Cheers

 On Mon, Aug 28, 2017 at 7:38 AM, Sridhar Chellappa <
 flinken...@gmail.com> wrote:

> Folks,
>
> I have a KafkaConsumer that I am trying to read messages from. When I
> try to create a DataStream from the KafkConsumer (env.addSource()) I get
> the following exception :
>
> Any idea on how can this happen?
>
> java.lang.NullPointerException
>   at 
> org.apache.flink.streaming.runtime.tasks.OperatorChain$CopyingChainingOutput.pushToOperator(OperatorChain.java:526)
>   at 
> org.apache.flink.streaming.runtime.tasks.OperatorChain$CopyingChainingOutput.collect(OperatorChain.java:503)
>   at 
> org.apache.flink.streaming.runtime.tasks.OperatorChain$CopyingChainingOutput.collect(OperatorChain.java:483)
>   at 
> org.apache.flink.streaming.api.operators.AbstractStreamOperator$CountingOutput.collect(AbstractStreamOperator.java:891)
>   at 
> org.apache.flink.streaming.api.operators.AbstractStreamOperator$CountingOutput.collect(AbstractStreamOperator.java:869)
>   at 
> org.apache.flink.streaming.api.operators.StreamSourceContexts$NonTimestampContext.collect(StreamSourceContexts.java:103)
>   at 
> org.apache.flink.streaming.api.operators.StreamSourceContexts$NonTimestampContext.collectWithTimestamp(StreamSourceContexts.java:110)
>   at 
> org.apache.flink.streaming.connectors.kafka.internals.AbstractFetcher.emitRecordWithTimestamp(AbstractFetcher.java:264)
>   at 
> org.apache.flink.streaming.connectors.kafka.internal.Kafka010Fetcher.emitRecord(Kafka010Fetcher.java:86)
>   at 
> org.apache.flink.streaming.connectors.kafka.internal.Kafka09Fetcher.runFetchLoop(Kafka09Fetcher.java:149)
>   at 
> org.apache.flink.streaming.connectors.kafka.FlinkKafkaConsumerBase.run(FlinkKafkaConsumerBase.java:449)
>   at 
> org.apache.flink.streaming.api.operators.StreamSource.run(StreamSource.java:87)
>   at 
> org.apache.flink.streaming.api.operators.StreamSource.run(StreamSource.java:55)
>   at 
> org.apache.flink.streaming.runtime.tasks.SourceStreamTask.run(SourceStreamTask.java:95)
>   at 
> org.apache.flink.streaming.runtime.tasks.StreamTask.invoke(StreamTask.java:262)
>   at org.apache.flink.runtime.taskmanager.Task.run(Task.java:702)
>   at java.lang.Thread.run(Thread.java:748)
>
>

>>>
>>
>

Re: Null Pointer Exception on Trying to read a message from Kafka

[Sridhar Chellappa]

1.3.0

On Mon, Aug 28, 2017 at 10:09 PM, Ted Yu  wrote:

> Which Flink version are you using (so that line numbers can be matched
> with source code) ?
>
> On Mon, Aug 28, 2017 at 9:16 AM, Sridhar Chellappa 
> wrote:
>
>> DataStream MyKafkaMessageDataStream = env.addSource(
>> getStreamSource(env, parameterTool);
>> );
>>
>>
>>
>> public RichParallelSourceFunction
>> getStreamSource(StreamExecutionEnvironment env, ParameterTool
>> parameterTool) {
>>
>>// MyKAfkaMessage is a ProtoBuf message
>> 
>> env.getConfig().registerTypeWithKryoSerializer(MyKafkaMessage.class,
>> ProtobufSerializer.class);
>>
>> KafkaDataSource flinkCepConsumer =
>> new KafkaDataSource(parameterTool,
>> new MyKafkaMessageSerDeSchema());
>>
>> return flinkCepConsumer;
>> }
>>
>>
>> public class KafkaDataSource extends FlinkKafkaConsumer010 {
>>
>> public KafkaDataSource(ParameterTool parameterTool,
>> DeserializationSchema deserializer) {
>> super(
>> Arrays.asList(parameterTool.ge
>> tRequired("topic").split(",")),
>> deserializer,
>> parameterTool.getProperties()
>> );
>>
>> }
>>
>> }
>>
>> public class MyKafkaMessageSerDeSchema implements
>> DeserializationSchema, SerializationSchema
>> {
>>
>> @Override
>> public MyKafkaMessage deserialize(byte[] message) throws IOException {
>> MyKafkaMessage MyKafkaMessage = null;
>> try {
>> MyKafkaMessage =  MyKafkaMessage.parseFrom(message);
>> } catch (InvalidProtocolBufferException e) {
>> e.printStackTrace();
>> } finally {
>> return MyKafkaMessage;
>> }
>> }
>>
>> @Override
>> public boolean isEndOfStream(MyKafkaMessage nextElement) {
>> return false;
>> }
>>
>> @Override
>> public TypeInformation getProducedType() {
>> return null;
>> }
>>
>> @Override
>> public byte[] serialize(MyKafkaMessage element) {
>> return new byte[0];
>> }
>> }
>>
>> On Mon, Aug 28, 2017 at 8:26 PM, Ted Yu  wrote:
>>
>>> Which version of Flink / Kafka are you using ?
>>>
>>> Can you show the snippet of code where you create the DataStream ?
>>>
>>> Cheers
>>>
>>> On Mon, Aug 28, 2017 at 7:38 AM, Sridhar Chellappa >> > wrote:
>>>
 Folks,

 I have a KafkaConsumer that I am trying to read messages from. When I
 try to create a DataStream from the KafkConsumer (env.addSource()) I get
 the following exception :

 Any idea on how can this happen?

 java.lang.NullPointerException
at 
 org.apache.flink.streaming.runtime.tasks.OperatorChain$CopyingChainingOutput.pushToOperator(OperatorChain.java:526)
at 
 org.apache.flink.streaming.runtime.tasks.OperatorChain$CopyingChainingOutput.collect(OperatorChain.java:503)
at 
 org.apache.flink.streaming.runtime.tasks.OperatorChain$CopyingChainingOutput.collect(OperatorChain.java:483)
at 
 org.apache.flink.streaming.api.operators.AbstractStreamOperator$CountingOutput.collect(AbstractStreamOperator.java:891)
at 
 org.apache.flink.streaming.api.operators.AbstractStreamOperator$CountingOutput.collect(AbstractStreamOperator.java:869)
at 
 org.apache.flink.streaming.api.operators.StreamSourceContexts$NonTimestampContext.collect(StreamSourceContexts.java:103)
at 
 org.apache.flink.streaming.api.operators.StreamSourceContexts$NonTimestampContext.collectWithTimestamp(StreamSourceContexts.java:110)
at 
 org.apache.flink.streaming.connectors.kafka.internals.AbstractFetcher.emitRecordWithTimestamp(AbstractFetcher.java:264)
at 
 org.apache.flink.streaming.connectors.kafka.internal.Kafka010Fetcher.emitRecord(Kafka010Fetcher.java:86)
at 
 org.apache.flink.streaming.connectors.kafka.internal.Kafka09Fetcher.runFetchLoop(Kafka09Fetcher.java:149)
at 
 org.apache.flink.streaming.connectors.kafka.FlinkKafkaConsumerBase.run(FlinkKafkaConsumerBase.java:449)
at 
 org.apache.flink.streaming.api.operators.StreamSource.run(StreamSource.java:87)
at 
 org.apache.flink.streaming.api.operators.StreamSource.run(StreamSource.java:55)
at 
 org.apache.flink.streaming.runtime.tasks.SourceStreamTask.run(SourceStreamTask.java:95)
at 
 org.apache.flink.streaming.runtime.tasks.StreamTask.invoke(StreamTask.java:262)
at org.apache.flink.runtime.taskmanager.Task.run(Task.java:702)
at java.lang.Thread.run(Thread.java:748)


>>>
>>
>

Re: Null Pointer Exception on Trying to read a message from Kafka

[Ted Yu]

Which Flink version are you using (so that line numbers can be matched with
source code) ?

On Mon, Aug 28, 2017 at 9:16 AM, Sridhar Chellappa 
wrote:

> DataStream MyKafkaMessageDataStream = env.addSource(
> getStreamSource(env, parameterTool);
> );
>
>
>
> public RichParallelSourceFunction 
> getStreamSource(StreamExecutionEnvironment
> env, ParameterTool parameterTool) {
>
>// MyKAfkaMessage is a ProtoBuf message
> 
> env.getConfig().registerTypeWithKryoSerializer(MyKafkaMessage.class,
> ProtobufSerializer.class);
>
> KafkaDataSource flinkCepConsumer =
> new KafkaDataSource(parameterTool,
> new MyKafkaMessageSerDeSchema());
>
> return flinkCepConsumer;
> }
>
>
> public class KafkaDataSource extends FlinkKafkaConsumer010 {
>
> public KafkaDataSource(ParameterTool parameterTool,
> DeserializationSchema deserializer) {
> super(
> Arrays.asList(parameterTool.getRequired("topic").split(","
> )),
> deserializer,
> parameterTool.getProperties()
> );
>
> }
>
> }
>
> public class MyKafkaMessageSerDeSchema implements 
> DeserializationSchema,
> SerializationSchema {
>
> @Override
> public MyKafkaMessage deserialize(byte[] message) throws IOException {
> MyKafkaMessage MyKafkaMessage = null;
> try {
> MyKafkaMessage =  MyKafkaMessage.parseFrom(message);
> } catch (InvalidProtocolBufferException e) {
> e.printStackTrace();
> } finally {
> return MyKafkaMessage;
> }
> }
>
> @Override
> public boolean isEndOfStream(MyKafkaMessage nextElement) {
> return false;
> }
>
> @Override
> public TypeInformation getProducedType() {
> return null;
> }
>
> @Override
> public byte[] serialize(MyKafkaMessage element) {
> return new byte[0];
> }
> }
>
> On Mon, Aug 28, 2017 at 8:26 PM, Ted Yu  wrote:
>
>> Which version of Flink / Kafka are you using ?
>>
>> Can you show the snippet of code where you create the DataStream ?
>>
>> Cheers
>>
>> On Mon, Aug 28, 2017 at 7:38 AM, Sridhar Chellappa 
>> wrote:
>>
>>> Folks,
>>>
>>> I have a KafkaConsumer that I am trying to read messages from. When I
>>> try to create a DataStream from the KafkConsumer (env.addSource()) I get
>>> the following exception :
>>>
>>> Any idea on how can this happen?
>>>
>>> java.lang.NullPointerException
>>> at 
>>> org.apache.flink.streaming.runtime.tasks.OperatorChain$CopyingChainingOutput.pushToOperator(OperatorChain.java:526)
>>> at 
>>> org.apache.flink.streaming.runtime.tasks.OperatorChain$CopyingChainingOutput.collect(OperatorChain.java:503)
>>> at 
>>> org.apache.flink.streaming.runtime.tasks.OperatorChain$CopyingChainingOutput.collect(OperatorChain.java:483)
>>> at 
>>> org.apache.flink.streaming.api.operators.AbstractStreamOperator$CountingOutput.collect(AbstractStreamOperator.java:891)
>>> at 
>>> org.apache.flink.streaming.api.operators.AbstractStreamOperator$CountingOutput.collect(AbstractStreamOperator.java:869)
>>> at 
>>> org.apache.flink.streaming.api.operators.StreamSourceContexts$NonTimestampContext.collect(StreamSourceContexts.java:103)
>>> at 
>>> org.apache.flink.streaming.api.operators.StreamSourceContexts$NonTimestampContext.collectWithTimestamp(StreamSourceContexts.java:110)
>>> at 
>>> org.apache.flink.streaming.connectors.kafka.internals.AbstractFetcher.emitRecordWithTimestamp(AbstractFetcher.java:264)
>>> at 
>>> org.apache.flink.streaming.connectors.kafka.internal.Kafka010Fetcher.emitRecord(Kafka010Fetcher.java:86)
>>> at 
>>> org.apache.flink.streaming.connectors.kafka.internal.Kafka09Fetcher.runFetchLoop(Kafka09Fetcher.java:149)
>>> at 
>>> org.apache.flink.streaming.connectors.kafka.FlinkKafkaConsumerBase.run(FlinkKafkaConsumerBase.java:449)
>>> at 
>>> org.apache.flink.streaming.api.operators.StreamSource.run(StreamSource.java:87)
>>> at 
>>> org.apache.flink.streaming.api.operators.StreamSource.run(StreamSource.java:55)
>>> at 
>>> org.apache.flink.streaming.runtime.tasks.SourceStreamTask.run(SourceStreamTask.java:95)
>>> at 
>>> org.apache.flink.streaming.runtime.tasks.StreamTask.invoke(StreamTask.java:262)
>>> at org.apache.flink.runtime.taskmanager.Task.run(Task.java:702)
>>> at java.lang.Thread.run(Thread.java:748)
>>>
>>>
>>
>

Re: Null Pointer Exception on Trying to read a message from Kafka

[Sridhar Chellappa]

DataStream MyKafkaMessageDataStream = env.addSource(
getStreamSource(env, parameterTool);
);



public RichParallelSourceFunction
getStreamSource(StreamExecutionEnvironment env, ParameterTool
parameterTool) {

   // MyKAfkaMessage is a ProtoBuf message

env.getConfig().registerTypeWithKryoSerializer(MyKafkaMessage.class,
ProtobufSerializer.class);

KafkaDataSource flinkCepConsumer =
new KafkaDataSource(parameterTool, new
MyKafkaMessageSerDeSchema());

return flinkCepConsumer;
}


public class KafkaDataSource extends FlinkKafkaConsumer010 {

public KafkaDataSource(ParameterTool parameterTool,
DeserializationSchema deserializer) {
super(

Arrays.asList(parameterTool.getRequired("topic").split(",")),
deserializer,
parameterTool.getProperties()
);

}

}

public class MyKafkaMessageSerDeSchema implements
DeserializationSchema, SerializationSchema {

@Override
public MyKafkaMessage deserialize(byte[] message) throws IOException {
MyKafkaMessage MyKafkaMessage = null;
try {
MyKafkaMessage =  MyKafkaMessage.parseFrom(message);
} catch (InvalidProtocolBufferException e) {
e.printStackTrace();
} finally {
return MyKafkaMessage;
}
}

@Override
public boolean isEndOfStream(MyKafkaMessage nextElement) {
return false;
}

@Override
public TypeInformation getProducedType() {
return null;
}

@Override
public byte[] serialize(MyKafkaMessage element) {
return new byte[0];
}
}

On Mon, Aug 28, 2017 at 8:26 PM, Ted Yu  wrote:

> Which version of Flink / Kafka are you using ?
>
> Can you show the snippet of code where you create the DataStream ?
>
> Cheers
>
> On Mon, Aug 28, 2017 at 7:38 AM, Sridhar Chellappa 
> wrote:
>
>> Folks,
>>
>> I have a KafkaConsumer that I am trying to read messages from. When I try
>> to create a DataStream from the KafkConsumer (env.addSource()) I get the
>> following exception :
>>
>> Any idea on how can this happen?
>>
>> java.lang.NullPointerException
>>  at 
>> org.apache.flink.streaming.runtime.tasks.OperatorChain$CopyingChainingOutput.pushToOperator(OperatorChain.java:526)
>>  at 
>> org.apache.flink.streaming.runtime.tasks.OperatorChain$CopyingChainingOutput.collect(OperatorChain.java:503)
>>  at 
>> org.apache.flink.streaming.runtime.tasks.OperatorChain$CopyingChainingOutput.collect(OperatorChain.java:483)
>>  at 
>> org.apache.flink.streaming.api.operators.AbstractStreamOperator$CountingOutput.collect(AbstractStreamOperator.java:891)
>>  at 
>> org.apache.flink.streaming.api.operators.AbstractStreamOperator$CountingOutput.collect(AbstractStreamOperator.java:869)
>>  at 
>> org.apache.flink.streaming.api.operators.StreamSourceContexts$NonTimestampContext.collect(StreamSourceContexts.java:103)
>>  at 
>> org.apache.flink.streaming.api.operators.StreamSourceContexts$NonTimestampContext.collectWithTimestamp(StreamSourceContexts.java:110)
>>  at 
>> org.apache.flink.streaming.connectors.kafka.internals.AbstractFetcher.emitRecordWithTimestamp(AbstractFetcher.java:264)
>>  at 
>> org.apache.flink.streaming.connectors.kafka.internal.Kafka010Fetcher.emitRecord(Kafka010Fetcher.java:86)
>>  at 
>> org.apache.flink.streaming.connectors.kafka.internal.Kafka09Fetcher.runFetchLoop(Kafka09Fetcher.java:149)
>>  at 
>> org.apache.flink.streaming.connectors.kafka.FlinkKafkaConsumerBase.run(FlinkKafkaConsumerBase.java:449)
>>  at 
>> org.apache.flink.streaming.api.operators.StreamSource.run(StreamSource.java:87)
>>  at 
>> org.apache.flink.streaming.api.operators.StreamSource.run(StreamSource.java:55)
>>  at 
>> org.apache.flink.streaming.runtime.tasks.SourceStreamTask.run(SourceStreamTask.java:95)
>>  at 
>> org.apache.flink.streaming.runtime.tasks.StreamTask.invoke(StreamTask.java:262)
>>  at org.apache.flink.runtime.taskmanager.Task.run(Task.java:702)
>>  at java.lang.Thread.run(Thread.java:748)
>>
>>
>

Re: Null Pointer Exception on Trying to read a message from Kafka

[Ted Yu]

Which version of Flink / Kafka are you using ?

Can you show the snippet of code where you create the DataStream ?

Cheers

On Mon, Aug 28, 2017 at 7:38 AM, Sridhar Chellappa 
wrote:

> Folks,
>
> I have a KafkaConsumer that I am trying to read messages from. When I try
> to create a DataStream from the KafkConsumer (env.addSource()) I get the
> following exception :
>
> Any idea on how can this happen?
>
> java.lang.NullPointerException
>   at 
> org.apache.flink.streaming.runtime.tasks.OperatorChain$CopyingChainingOutput.pushToOperator(OperatorChain.java:526)
>   at 
> org.apache.flink.streaming.runtime.tasks.OperatorChain$CopyingChainingOutput.collect(OperatorChain.java:503)
>   at 
> org.apache.flink.streaming.runtime.tasks.OperatorChain$CopyingChainingOutput.collect(OperatorChain.java:483)
>   at 
> org.apache.flink.streaming.api.operators.AbstractStreamOperator$CountingOutput.collect(AbstractStreamOperator.java:891)
>   at 
> org.apache.flink.streaming.api.operators.AbstractStreamOperator$CountingOutput.collect(AbstractStreamOperator.java:869)
>   at 
> org.apache.flink.streaming.api.operators.StreamSourceContexts$NonTimestampContext.collect(StreamSourceContexts.java:103)
>   at 
> org.apache.flink.streaming.api.operators.StreamSourceContexts$NonTimestampContext.collectWithTimestamp(StreamSourceContexts.java:110)
>   at 
> org.apache.flink.streaming.connectors.kafka.internals.AbstractFetcher.emitRecordWithTimestamp(AbstractFetcher.java:264)
>   at 
> org.apache.flink.streaming.connectors.kafka.internal.Kafka010Fetcher.emitRecord(Kafka010Fetcher.java:86)
>   at 
> org.apache.flink.streaming.connectors.kafka.internal.Kafka09Fetcher.runFetchLoop(Kafka09Fetcher.java:149)
>   at 
> org.apache.flink.streaming.connectors.kafka.FlinkKafkaConsumerBase.run(FlinkKafkaConsumerBase.java:449)
>   at 
> org.apache.flink.streaming.api.operators.StreamSource.run(StreamSource.java:87)
>   at 
> org.apache.flink.streaming.api.operators.StreamSource.run(StreamSource.java:55)
>   at 
> org.apache.flink.streaming.runtime.tasks.SourceStreamTask.run(SourceStreamTask.java:95)
>   at 
> org.apache.flink.streaming.runtime.tasks.StreamTask.invoke(StreamTask.java:262)
>   at org.apache.flink.runtime.taskmanager.Task.run(Task.java:702)
>   at java.lang.Thread.run(Thread.java:748)
>
>