It means more than on dependency is pulling a different version of slf4j. Class loader is loading a version that doesn't have StaticLoggerBinder.getSingleton() method. To check which dependencies are pulling in different versions of slf4j use maven dependency:tree
The exact command is
mvn dependency:tree -DoutputFile=/somepath/file.txt
BWT lastet one available is
<dependency>
<groupId>org.slf4j</groupId>
<artifactId>slf4j-api</artifactId>
<version>1.7.7</version>
</dependency>
Hope this helps.