(Reading database ... 177489 files and directories currently installed.)
Preparing to unpack elasticsearch_1.7.3+dfsg-3_all.deb ...
The system user `elasticsearch' already exists. Exiting.
Unpacking elasticsearch (1.7.3+dfsg-3) over (1.7.3+dfsg-3) ...
dpkg: dependency problems prevent configuration of elasticsearch:
 elasticsearch depends on default-jre-headless | java6-runtime-headless; however:
  Package default-jre-headless is not installed.
  Package java6-runtime-headless is not installed.
 elasticsearch depends on libelasticsearch1.7-java; however:
  Package libelasticsearch1.7-java is not installed.
 elasticsearch depends on java-wrappers; however:
  Package java-wrappers is not installed.

dpkg: error processing package elasticsearch (--install):
 dependency problems - leaving unconfigured
Processing triggers for systemd (237-3ubuntu10.15) ...
Processing triggers for ureadahead (0.100.0-20) ...
Errors were encountered while processing:
 elasticsearch