Connecting Elasticsearch in Ubuntu 17.04

Java version: 1.8

openjdk version "1.8.0_151"
OpenJDK Runtime Environment (build 1.8.0_151-8u151-b12-0ubuntu0.17.04.2-b12)
OpenJDK 64-Bit Server VM (build 25.151-b12, mixed mode)

Elasticsearch version: 2.3.1