Hi Vinayak,

For embedded use of janusgraph, see:
https://docs.janusgraph.org/getting-started/basic-usage/#loading-with-an-index-backend
and replace the properties file with the one currently used by gremlin server.

With embedded use, you can simply do (if your graph is not too large):
vertices = g.V().toList()
edges = g.E().toList()
subGraph = g.E().subgraph('sub').cap('sub').next()

Best wishes,   Marc