NoClassDefFound exception after setting spark.eventLog.enabled=true

["C. Josephson" <cj...@uhana.io>]

I use Spark 1.6.2 with Java, and after I set spark.eventLog.enabled=true
spark crashes with this exception:

Exception in thread "main" java.lang.NoClassDefFoundError:
org/json4s/jackson/JsonMethods$
at
org.apache.spark.scheduler.EventLoggingListener$.initEventLog(EventLoggingListener.scala:257)
at
org.apache.spark.scheduler.EventLoggingListener.start(EventLoggingListener.scala:124)
at org.apache.spark.SparkContext.<init>(SparkContext.scala:519)
at
org.apache.spark.api.java.JavaSparkContext.<init>(JavaSparkContext.scala:58)
at
com.uhana.stream.UhanaStreamingContext.<init>(UhanaStreamingContext.java:165)
at
com.uhana.stream.UhanaStreamingContext.<init>(UhanaStreamingContext.java:23)
at
com.uhana.stream.UhanaStreamingContext$Builder.build(UhanaStreamingContext.java:159)
at com.uhana.stream.app.StreamingMain.main(StreamingMain.java:41)
Caused by: java.lang.ClassNotFoundException: org.json4s.jackson.JsonMethods$
at java.net.URLClassLoader.findClass(URLClassLoader.java:381)
at java.lang.ClassLoader.loadClass(ClassLoader.java:424)
at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:331)
at java.lang.ClassLoader.loadClass(ClassLoader.java:357)
... 8 more

I downloaded some jars for json4s, but I'm not sure where they should go.

Thanks,
-cjosephson