{"action":"created","issue":{"url":"https://api.github.com/repos/PredictionIO/template-scala-parallel-universal-recommendation/issues/2","labels_url":"https://api.github.com/repos/PredictionIO/template-scala-parallel-universal-recommendation/issues/2/labels{/name}","comments_url":"https://api.github.com/repos/PredictionIO/template-scala-parallel-universal-recommendation/issues/2/comments","events_url":"https://api.github.com/repos/PredictionIO/template-scala-parallel-universal-recommendation/issues/2/events","html_url":"https://github.com/PredictionIO/template-scala-parallel-universal-recommendation/issues/2","id":97705160,"number":2,"title":"Getting \"empty collection\" exception - no other information","user":{"login":"armahajan","id":7665039,"avatar_url":"https://avatars.githubusercontent.com/u/7665039?v=3","gravatar_id":"","url":"https://api.github.com/users/armahajan","html_url":"https://github.com/armahajan","followers_url":"https://api.github.com/users/armahajan/followers","following_url":"https://api.github.com/users/armahajan/following{/other_user}","gists_url":"https://api.github.com/users/armahajan/gists{/gist_id}","starred_url":"https://api.github.com/users/armahajan/starred{/owner}{/repo}","subscriptions_url":"https://api.github.com/users/armahajan/subscriptions","organizations_url":"https://api.github.com/users/armahajan/orgs","repos_url":"https://api.github.com/users/armahajan/repos","events_url":"https://api.github.com/users/armahajan/events{/privacy}","received_events_url":"https://api.github.com/users/armahajan/received_events","type":"User","site_admin":false},"labels":[],"state":"open","locked":false,"assignee":null,"milestone":null,"comments":4,"created_at":"2015-07-28T13:22:27Z","updated_at":"2015-07-29T10:07:09Z","closed_at":null,"body":"I am getting Exception in thread \"main\" java.lang.UnsupportedOperationException: empty collection on step 41 or so while the engine is training. There is no other debugging information. What could be the issue here?\r\n\r\nI have $set users, items and view and purchase events and made sure the data is logically connected between these.\r\n\r\nThanks in advance for your help!\r\n\r\nRegards,\r\nAkshay Mahajan"},"comment":{"url":"https://api.github.com/repos/PredictionIO/template-scala-parallel-universal-recommendation/issues/comments/125905586","html_url":"https://github.com/PredictionIO/template-scala-parallel-universal-recommendation/issues/2#issuecomment-125905586","issue_url":"https://api.github.com/repos/PredictionIO/template-scala-parallel-universal-recommendation/issues/2","id":125905586,"user":{"login":"armahajan","id":7665039,"avatar_url":"https://avatars.githubusercontent.com/u/7665039?v=3","gravatar_id":"","url":"https://api.github.com/users/armahajan","html_url":"https://github.com/armahajan","followers_url":"https://api.github.com/users/armahajan/followers","following_url":"https://api.github.com/users/armahajan/following{/other_user}","gists_url":"https://api.github.com/users/armahajan/gists{/gist_id}","starred_url":"https://api.github.com/users/armahajan/starred{/owner}{/repo}","subscriptions_url":"https://api.github.com/users/armahajan/subscriptions","organizations_url":"https://api.github.com/users/armahajan/orgs","repos_url":"https://api.github.com/users/armahajan/repos","events_url":"https://api.github.com/users/armahajan/events{/privacy}","received_events_url":"https://api.github.com/users/armahajan/received_events","type":"User","site_admin":false},"created_at":"2015-07-29T10:07:09Z","updated_at":"2015-07-29T10:07:09Z","body":"ok - I found that add-to-cart was declared in my eventNames but did not have a single event of that type. After removing, training part gets through. Now getting another exception. IS this because no previous indexes have been created to delete? In that case code should handle empty index collection case? Or something similar. Full trace below.\r\n\r\n[INFO] [URModel] Deleting index: /urindex/item\r\nException in thread \"main\" org.elasticsearch.client.transport.NoNodeAvailableException: None of the configured nodes are available: []\r\n        at org.elasticsearch.client.transport.TransportClientNodesService.ensureNodesAreAvailable(TransportClientNodesService.java:278)\r\n        at org.elasticsearch.client.transport.TransportClientNodesService.execute(TransportClientNodesService.java:197)\r\n        at org.elasticsearch.client.transport.support.InternalTransportIndicesAdminClient.execute(InternalTransportIndicesAdminClient.java:86)\r\n        at org.elasticsearch.client.transport.support.InternalTransportIndicesAdminClient.execute(InternalTransportIndicesAdminClient.java:77)\r\n        at org.elasticsearch.client.support.AbstractIndicesAdminClient.exists(AbstractIndicesAdminClient.java:165)\r\n        at com.ignitiv.esClient$.deleteIndex(esClient.scala:30)\r\n        at com.ignitiv.URModel.save(URModel.scala:72)\r\n        at com.ignitiv.URModel.save(URModel.scala:15)\r\n        at io.prediction.controller.P2LAlgorithm.makePersistentModel(P2LAlgorithm.scala:111)\r\n        at io.prediction.controller.Engine$$anonfun$makeSerializableModels$2.apply(Engine.scala:294)\r\n        at io.prediction.controller.Engine$$anonfun$makeSerializableModels$2.apply(Engine.scala:293)\r\n        at scala.collection.TraversableLike$$anonfun$map$1.apply(TraversableLike.scala:244)\r\n        at scala.collection.TraversableLike$$anonfun$map$1.apply(TraversableLike.scala:244)\r\n        at scala.collection.Iterator$class.foreach(Iterator.scala:727)\r\n        at scala.collection.AbstractIterator.foreach(Iterator.scala:1157)\r\n        at scala.collection.IterableLike$class.foreach(IterableLike.scala:72)\r\n        at scala.collection.AbstractIterable.foreach(Iterable.scala:54)\r\n        at scala.collection.TraversableLike$class.map(TraversableLike.scala:244)\r\n        at scala.collection.AbstractTraversable.map(Traversable.scala:105)\r\n        at io.prediction.controller.Engine.makeSerializableModels(Engine.scala:293)\r\n        at io.prediction.controller.Engine.train(Engine.scala:185)\r\n        at io.prediction.workflow.CoreWorkflow$.runTrain(CoreWorkflow.scala:65)\r\n        at io.prediction.workflow.CreateWorkflow$.main(CreateWorkflow.scala:246)\r\n        at io.prediction.workflow.CreateWorkflow.main(CreateWorkflow.scala)\r\n        at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)\r\n        at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)\r\n        at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)\r\n        at java.lang.reflect.Method.invoke(Method.java:606)\r\n        at org.apache.spark.deploy.SparkSubmit$.org$apache$spark$deploy$SparkSubmit$$runMain(SparkSubmit.scala:569)\r\n        at org.apache.spark.deploy.SparkSubmit$.doRunMain$1(SparkSubmit.scala:166)\r\n        at org.apache.spark.deploy.SparkSubmit$.submit(SparkSubmit.scala:189)\r\n        at org.apache.spark.deploy.SparkSubmit$.main(SparkSubmit.scala:110)\r\n        at org.apache.spark.deploy.SparkSubmit.main(SparkSubmit.scala)\r\n"}}