From private mail:
"I have created directory under git folder and restarted gerrit service . but its not reflecting on UI though it runs perfectly on version 2.15."
From private mail:
"""java -jar gerrit-3.4.0.war reindex -d GerritSiteDir/review_site/git/Android-R0
fatal: not a Gerrit site: 'GerritSiteDir/review_site/git/Android-R0'
fatal: Perhaps you need to run init first? """
-d should be set to the Gerrit site root wich in you case shold be "GerritSiteDir/review_site"
java -jar gerrit-3.4.0.war reindex -d GerritSiteDir/review_site --index projects