Issue with elastic search 5.0.0 - NoClassDefFoundError: org/apache/logging/log4j/Logger

[Fabrizio_Fortino]

https://www.elastic.co/guide/en/elasticsearch/reference/5.0/breaking_50_java_api_changes.html#_elasticsearch_will_no_longer_detect_logging_implementations

With ES 5 you have to explicitly include Log4J 2 as dependency in your pom.