Description
My question is https://github.com/apache/spark/blob/master/examples/src/main/java/org/apache/spark/examples/streaming/JavaKafkaWordCount.java correct?
I'm pretty new to both Spark and Java. I wanted to find an example of Spark Streaming using Java, streaming from Kafka. The JavaKafkaWordCount at https://github.com/apache/spark/blob/master/examples/src/main/java/org/apache/spark/examples/streaming/JavaKafkaWordCount.java looked to be perfect.
However, when I tried running it, I found a couple of issues that I needed to overcome.
1. This line was unnecessary:
StreamingExamples.setStreamingLogLevels();
Having this line in there (and the associated import) caused me to go looking for a dependency spark-examples_2.10 which of no real use to me.
2. After running it, this line:
JavaPairReceiverInputDStream<String, String> messages = KafkaUtils.createStream(jssc, args[0], args[1], topicMap);
Appeared to throw an error around logging:
Exception in thread "main" java.lang.NoClassDefFoundError: org/apache/spark/Logging at java.lang.ClassLoader.defineClass1(Native Method) at java.lang.ClassLoader.defineClass(ClassLoader.java:763) at java.security.SecureClassLoader.defineClass(SecureClassLoader.java:142) at java.net.URLClassLoader.defineClass(URLClassLoader.java:467) at java.net.URLClassLoader.access$100(URLClassLoader.java:73) at java.net.URLClassLoader$1.run(URLClassLoader.java:368) at java.net.URLClassLoader$1.run(URLClassLoader.java:362) at java.security.AccessController.doPrivileged(Native Method) at java.net.URLClassLoader.findClass(URLClassLoader.java:361) at java.lang.ClassLoader.loadClass(ClassLoader.java:424) at java.lang.ClassLoader.loadClass(ClassLoader.java:357) at org.apache.spark.streaming.kafka.KafkaUtils$.createStream(KafkaUtils.scala:91 at org.apache.spark.streaming.kafka.KafkaUtils$.createStream(KafkaUtils.scala:66 at org.apache.spark.streaming.kafka.KafkaUtils$.createStream(KafkaUtils.scala:11 at org.apache.spark.streaming.kafka.KafkaUtils.createStream(KafkaUtils.scala) at main.java.com.cm.JavaKafkaWordCount.main(JavaKafkaWordCount.java:72)
To get around this, I found that the code sample in https://spark.apache.org/docs/latest/streaming-kafka-0-10-integration.html helped me to come up with the right lines to see streaming from Kafka in action. Specifically this called createDirectStream instead of createStream.
So is the example in https://github.com/apache/spark/blob/master/examples/src/main/java/org/apache/spark/examples/streaming/JavaKafkaWordCount.java or is there something I could have done differently to get that example working?
Attachments
Issue Links
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SPARK-20238 Is the JavaDirectKafkaWordCount example correct for Spark version 2.1?
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- Closed
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