sqldeveloper ORA-12505. TNS: listener does not currently know of SID given in connect descriptor
You have to use Service Names to connect to Pluggable Databases in 12c.
It's just one of those things that can trip you up, I guess! SQL Plus connecting OK probably threw you.
I had the same problem. And I solved it by using SERVICE NAME (an alias) instead of SID:
1. Open file tnsnames.ora from your ORACLE_HOME folder. In case you don't know its location, do the following steps
Windows (open cmd)
> sqlplus // connect to sqlplus, login as sysdba
as / sysdba
// then type your password that you set in configuration setup step
// next 3 lines used for getting ORACLE_HOME
> var OHM varchar2(100);
> EXEC dbms_system.get_env('ORACLE_HOME', :OHM);
> PRINT OHM // ---> ORACLE_HOME
Linux (open Terminal Ctrl+Alt+T)
echo $ORACLE_HOME
tnsnames.ora is located at [Your_ORACLE_HOME]/Network/Admin. Open it with your editor.
2. In tnsnames.ora file, look for the line which contains the SERVICE_NAME
3. Select Service name and type above name, TEST success and you've done!
