Rename the file hawkular-inventory-impl-tinkerpop-tinkergraph-provider-1.1.3.Final-javadoc.jar to hawkular-inventory-impl-tinkerpop-tinkergraph-provider-1.1.3.Final-javadoc.zip
Use your favourite unzip tool (WinRAR / WinZIP) to extract it, now you have a folder hawkular-inventory-impl-tinkerpop-tinkergraph-provider-1.1.3.Final-javadoc
Double click index.html will open the index page on your default web browser.