Postgresql : Connection refused. Check that the hostname and port are correct and that the postmaster is accepting TCP/IP connections

I am trying to connect postgresql but I am getting this error.

org.postgresql.util.PSQLException: Connection refused. Check that the hostname and port are correct and that the postmaster is accepting TCP/IP connections.

My pg_hba.conf file is like this.

 TYPE  DATABASE        USER            CIDR-ADDRESS            METHOD

# IPv4 local connections:
host    all             all             127.0.0.1/32            md5
# IPv6 local connections:
host    all             all             ::1/128                 md5

I would be much obliged if anyone please be so kind enough to explain whats hoing on here and how should I correct it.