CODEWITHSUNDEEP
javascalamavennoclassdeffounderror
streamoverflowed
streamoverflowed

Reputation: 925

Kafka Consumer Example throws ClassNotFoundException

I have Kafka 0.8 built using Scala 2.8; the steps followed from this site. I could also run the kafka-console-producer and kafka-console-consumer examples successfully. I am now experimenting with Consumer Group Example (Please the "Full Source Code" section). The exception I get is below:

java.lang.reflect.InvocationTargetException
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
    at    sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.lang.reflect.Method.invoke(Method.java:622)
    at org.codehaus.mojo.exec.ExecJavaMojo$1.run(ExecJavaMojo.java:297)
    at java.lang.Thread.run(Thread.java:701)
Caused by: java.lang.NoClassDefFoundError: scala/Tuple2$mcJJ$sp
    at kafka.consumer.ConsumerConfig.<init>(Unknown Source)
    at ConsumerGroupExample.createConsumerConfig(ConsumerGroupExample.java:55)
    at ConsumerGroupExample.<init>(ConsumerGroupExample.java:18)
    at ConsumerGroupExample.main(ConsumerGroupExample.java:64)
    ... 6 more
Caused by: java.lang.ClassNotFoundException: scala.Tuple2$mcJJ$sp
    at java.net.URLClassLoader$1.run(URLClassLoader.java:217)
    at java.security.AccessController.doPrivileged(Native Method)
    at java.net.URLClassLoader.findClass(URLClassLoader.java:205)
    at java.lang.ClassLoader.loadClass(ClassLoader.java:323)
    at java.lang.ClassLoader.loadClass(ClassLoader.java:268)
    ... 10 more

My dependencies looks like this:

<dependencies>
  <dependency>
  <groupId>junit</groupId>
  <artifactId>junit</artifactId>
  <version>3.8.1</version>
  <scope>test</scope>
</dependency>
<dependency>
    <groupId>org.apache.kafka</groupId>
    <artifactId>kafka_2.10</artifactId>
    <version>0.8.0</version>
</dependency>
<dependency>
    <groupId>javax.inject</groupId>
    <artifactId>javax.inject</artifactId>
    <version>1</version>
</dependency>
<dependency>
    <groupId>org.scala-lang</groupId>
    <artifactId>scala-library</artifactId>
    <version>2.8.0</version>
</dependency>
<dependency>
    <groupId>log4j</groupId>
    <artifactId>log4j</artifactId>
    <version>1.2.17</version>
</dependency>
<dependency>
    <groupId>com.101tec</groupId>
    <artifactId>zkclient</artifactId>
    <version>0.3</version>
</dependency>
<dependency>
    <groupId>com.yammer.metrics</groupId>
    <artifactId>metrics-core</artifactId>
    <version>2.2.0</version>
</dependency>

As a note I could get it running with a Python client. But I really need this done in Java. Would really appreciate any help!

Upvotes: 1

Views: 3586

Answers (1)

om-nom-nom
om-nom-nom

Reputation: 62845

You're using kafka built against 2.10 (see, that _2.10 in artifact name)

<dependency>
    <groupId>org.apache.kafka</groupId>
    <artifactId>kafka_2.10</artifactId>
    <version>0.8.0</version>
</dependency>

with scala 2.8.0

<dependency>
    <groupId>org.scala-lang</groupId>
    <artifactId>scala-library</artifactId>
    <version>2.8.0</version>
</dependency>

Major scala versions (2.8.*, 2.9.*, 2.10.*) are binary incompatible between each other -- pick the right version of either kafka artifact or project's scala library and everything will be fine.

Upvotes: 2

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