Make sure slf4j-log4j12 is same version as slf4j-api
<groupId>org.apache.zookeeper</groupId>
<artifactId>zookeeper</artifactId>
</dependency>
+ <dependency>
+ <groupId>org.slf4j</groupId>
+ <artifactId>slf4j-log4j12</artifactId>
+ <version>1.7.5</version>
+ </dependency>
</dependencies>
<build>
<plugins>
