ORA-00604 ORA-12705

Try following:

1. Check that NLS_LANG setting is correct. On windows it is in registry under \HKEY_LOCAL_MACHINE\SOFTWARE\ORACLE.
2. Check that Oracle client software is correctly installed.
3. Check if there are multiple Oracle homes on that computer. In that case, find active one and check if it works.
4. Test with SQL*Plus if there is one installed. Sql Developer works because it has its own client installation.

Edit:
Regarding drivers, check this site: Oracle Instant Client. There you will find documentation on minimum drivers installation needed for JDBC access to Oracle. I don't know much about that because I use .Net.

Edit 2:
See this question: NLS_LANG setting for JDBC thin driver. There is same error as you have and problem was that default locale for NLS LANG was not defined. Quote:

The NLS_LANG settings are derived from the java.util.Locale . Therefore, you will need to make a call similar to this before connecting:

  Locale.setDefault(Locale.<your locale here>);

I figured out that that you could pass that two params to your Java app to resolve the issue:

-Duser.country=en -Duser.language=en

You could configure the values at environment variable level as well (depends from your OS).