ORA-01882: timezone region not found

If you get the following error when you try to connect to your Oracle db from SQL developer (or from any other entity)

ORA-01882: timezone region not found

The reason is that time zone is not set in java opts (Obviously!)  You need to set it.

In SQL developer go to

opt/sqldeveloper/sqldeveloper/bin/sqldeveloper.conf 

And add,

AddVMOption -Duser.timezone="+05:30" (Your time zone)