Unable to set guc via setProperty

Hi Team,
I've a doubt regarding passing guc variables in start up packet as key
value pairs instead of in options.

I'm unable to set jdbc:postgresql://10.150.3.175:6433/postgres?&geqo=off
m geqo to 'off'. I don't want to use "options" rather pass directly key
value pairs similar to what JDBC driver internally does.

Neither setProperty("geqo", "off") works in this case.
Can someone let me know why I can't do it?

I learnt or from code, it's seen the key value pairs has higher precedence
or override the guc values passed via cmdline option("options") field when
both passed in start up packet.
That's why with JDBC, even i try to set "options - DateStyle to
'Postgres,DM'Y'" we are unable to change value as DateStyle is also passed
as key value by driver with 'ISO' which has higher precedence.
Thanks
Manav