Elasticsearch "StatusLogger Log4j2 could not find a logging implementation. Please add log4j-core to the classpath."

Question

I upgraded elasticsearch java client from 2.3 to 5.1.

And this error log continues to appear.

ERROR StatusLogger Log4j2 could not find a logging implementation. Please add log4j-core to the classpath. Using SimpleLogger to log to the console...

I'm using log4j2

<dependency>
    <groupId>org.apache.logging.log4j</groupId>
    <artifactId>log4j-api</artifactId>
    <version>2.7</version>
</dependency>
<dependency>
    <groupId>org.apache.logging.log4j</groupId>
    <artifactId>log4j-core</artifactId>
    <version>2.7</version>
</dependency>

Answer 1

very late answer, however :) if you don't want to upgrade ES, just add following dependency to pom :

<dependency>
    <groupId>org.apache.logging.log4j</groupId>
    <artifactId>log4j-to-slf4j</artifactId>
    <version>2.8.2</version>
</dependency>

that should fix it