You should be able to control the language settings by adding statements like:
to the sqldeveloper.conf file (which is in folder sqldeveloper/sqldeveloper/bin).
You should close SQL Developer before editing this file.
No David, This is not what I am looking for. Your changes only affect the UI of the SQL Developer, which is fine for us to be displayed in English.
I am looking for configuring the client to display and store Arabic in the database. it is NLS_LANG issue. I cannot display Arabic String stored in database.