Kafka Quickstart: java.lang.NoClassDefFoundError: scala/ScalaObject

Kafka Quickstart: java.lang.NoClassDefFoundError: scala/ScalaObject

I am working through the kafka quickstart:
http://kafka.apache.org/07/quickstart.html
I have coded up the Consumer and ConsumerThreadPool examples, eg
import kafka.consumer.KafkaStream;
import kafka.consumer.ConsumerIterator;
public class Consumer implements Runnable {
private KafkaStream m_stream;
private Integer m_threadNumber;
public Consumer(KafkaStream a_stream, Integer a_threadNumber) {
m_threadNumber = a_threadNumber;
m_stream = a_stream;
}
public void run() {
ConsumerIterator<byte[], byte[]> it = m_stream.iterator();
while (it.hasNext()) {
System.out.println("Thread " + m_threadNumber + ": " + new
String(it.next().message()));
}
System.out.println("Shutting down Thread: " + m_threadNumber);
}
}
A couple of other facets: I am using spring to manage my zookeeper:
import javax.inject.Named;
import java.util.Properties;
import kafka.consumer.ConsumerConfig;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.ComponentScan;
import org.springframework.context.annotation.Configuration;
@Configuration
@ComponentScan("com.truecar.inventory.worker.core")
public class AppConfig {
@Bean
@Named("consumerConfig")
private static ConsumerConfig createConsumerConfig() {
String zookeeperAddress = "127.0.0.1:2181";
String groupId = "inventory";
Properties props = new Properties();
props.put("zookeeper.connect", zookeeperAddress);
props.put("group.id", groupId);
props.put("zookeeper.session.timeout.ms", "400");
props.put("zookeeper.sync.time.ms", "200");
props.put("auto.commit.interval.ms", "1000");
return new ConsumerConfig(props);
}
}
And I am compiling with Maven and the OneJar Maven plugin. However, I
compile and then run the resulting one jar I get the following error:
Aug 26, 2013 6:15:41 PM
org.springframework.context.annotation.ClassPathScanningCandidateComponentProvider
registerDefaultFilters
INFO: JSR-330 'javax.inject.Named' annotation found and supported for
component scanning
Exception in thread "main" 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:606)
at com.simontuffs.onejar.Boot.run(Boot.java:340)
at com.simontuffs.onejar.Boot.main(Boot.java:166)
Caused by: java.lang.NoClassDefFoundError: scala/ScalaObject
at java.lang.ClassLoader.defineClass1(Native Method)
at java.lang.ClassLoader.defineClass(ClassLoader.java:792)
at com.simontuffs.onejar.JarClassLoader.defineClass(JarClassLoader.java:803)
at com.simontuffs.onejar.JarClassLoader.findClass(JarClassLoader.java:710)
at java.lang.ClassLoader.loadClass(ClassLoader.java:424)
at com.simontuffs.onejar.JarClassLoader.loadClass(JarClassLoader.java:630)
at java.lang.ClassLoader.loadClass(ClassLoader.java:357)
at java.lang.Class.getDeclaredMethods0(Native Method)
at java.lang.Class.privateGetDeclaredMethods(Class.java:2521)
at java.lang.Class.getDeclaredMethods(Class.java:1845)
at
org.springframework.core.type.StandardAnnotationMetadata.getAnnotatedMethods(StandardAnnotationMetadata.java:180)
at
org.springframework.context.annotation.ConfigurationClassParser.doProcessConfigurationClass(ConfigurationClassParser.java:222)
at
org.springframework.context.annotation.ConfigurationClassParser.processConfigurationClass(ConfigurationClassParser.java:165)
at
org.springframework.context.annotation.ConfigurationClassParser.parse(ConfigurationClassParser.java:140)
at
org.springframework.context.annotation.ConfigurationClassPostProcessor.processConfigBeanDefinitions(ConfigurationClassPostProcessor.java:282)
at
org.springframework.context.annotation.ConfigurationClassPostProcessor.postProcessBeanDefinitionRegistry(ConfigurationClassPostProcessor.java:223)
at
org.springframework.context.support.AbstractApplicationContext.invokeBeanFactoryPostProcessors(AbstractApplicationContext.java:630)
at
org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:461)
at
org.springframework.context.annotation.AnnotationConfigApplicationContext.<init>(AnnotationConfigApplicationContext.java:73)
at
com.truecar.inventory.worker.core.consumer.ConsumerThreadPool.<clinit>(ConsumerThreadPool.java:31)
at
com.truecar.inventory.worker.core.application.Starter.main(Starter.java:20)
... 6 more
Caused by: java.lang.ClassNotFoundException: scala.ScalaObject
at com.simontuffs.onejar.JarClassLoader.findClass(JarClassLoader.java:713)
at java.lang.ClassLoader.loadClass(ClassLoader.java:424)
at com.simontuffs.onejar.JarClassLoader.loadClass(JarClassLoader.java:630)
at java.lang.ClassLoader.loadClass(ClassLoader.java:357)
... 27 more
Now, I know little about Kafka, and nothing about Scala. How do I fix
this? What should i try next? Is this a known issue? Do I need other
dependencies?