Debian and Postgres

Hello,

This is a Debian problem that has caused a problem starting Postgres.
So, I'm posting it here in the hope that somebody has experienced it
previously and can assist me in fixing it.

Yesterday, it started up as per normal and first command issued via
JDBC driver was run:-

2016-05-04 10:39:39 AESTLOG:  MultiXact member wraparound protections
are now enabled
2016-05-04 10:39:39 AESTLOG:  database system is ready to accept
connections
2016-05-04 10:39:39 AESTLOG:  autovacuum launcher started
2016-05-04 10:40:00 AESTLOG:  duration: 224.906 ms  parse <unnamed>:
SET extra_float_digits = 3


Today, the following was in the log:-

2016-05-05 03:44:53 AESTLOG:  test message did not get through on
socket for statistics collector
2016-05-05 03:44:53 AESTLOG:  disabling statistics collector for lack
of working socket
2016-05-05 03:44:53 AESTWARNING:  autovacuum not started because of
misconfiguration
2016-05-05 03:44:53 AESTHINT:  Enable the "track_counts" option.
2016-05-05 03:44:53 AESTLOG:  database system was shut down at 2016-05-
04 11:56:37 AEST
2016-05-05 03:44:54 AESTLOG:  MultiXact member wraparound protections
are now enabled
2016-05-05 03:44:54 AESTLOG:  database system is ready to accept
connections
2016-05-05 03:58:29 AESTLOG:  duration: 787.241 ms  statement: select
count(*) from boiler_plate;


Relative section of conf file unchanged for months:-

# - Query/Index Statistics Collector -

#track_activities = on
track_counts = on
#track_io_timing = off
#track_functions = none                 # none, pl, all
#track_activity_query_size = 1024       # (change requires restart)
stats_temp_directory = 'pg_stat_tmp'


# - Statistics Monitoring -

#log_parser_stats = off
#log_planner_stats = off
#log_executor_stats = off
#log_statement_stats = off


I can connect via psql and issue queries without any problems. Trying
to connect via JDBC fails. Trying to connect by an application fails.

I use synaptic for package management. Yesterday I was running short on
space and removed some packages described as *obsolete* by synaptic.
My guess is that a dependency chain is incorrect and a certain package
is not in fact obsolete.
For some reason the synaptic history log only shows tzdata-java as
being removed but in fact several libraries and other packages were
permanently removed. The dpkg logs only show installation details.
I don't know why synaptic failed to record the removals in its history
logs as if it had, then I could trawl thru the logs and restore the
missing packages.
The apt logs do not list removals either.

Versions:-

Java JDK version 1.8.0_91
Linux [ 4.5.0-1-amd64 ]
JDBC 9.4-1208
Postgres psql (9.5.2)
libpq5_9.5.2-1_amd64.deb


Any assistance appreciated.

Thanks,
Rob