The default database name is the one you provided while installing oracle. You can get it from the file -
<oracle_home>\network\ADMIN\tnsnames.ORA
It should look like this:
Here, "RAM" is the name of the default database I entered while installing oracle.
I could access my personal oracle by having SID = RAM in my
java program.
hope this helps!
[This message has been edited by sanjay yermalkar (edited October 29, 2001).]