Unable to figure out how a transitive dependency of a particular version is ending up in my jar?

Yes I got the same syntax problem so I tried this

configurations.all {
  resolutionStrategy {
    force "com.google.guava:guava:26.0-jre"
   }
}

Still the same result I see guava 19.0

#Generated by org.apache.felix.bundleplugin
#Wed Dec 09 15:58:23 EST 2015
version=19.0
groupId=com.google.guava
artifactId=guava